2022/08/17 更新

写真a

タキザワ ケンジ
滝沢 研二
所属
理工学術院 創造理工学部
職名
教授
ホームページ

兼担

  • 理工学術院   大学院創造理工学研究科

学内研究所等

  • 2020年
    -
    2022年

    理工学術院総合研究所   兼任研究員

学歴

  •  
    -
    2005年

    東京工業大学   総合理工学研究科   創造エネルギー  

  •  
    -
    2002年

    東京工業大学   総合理工学研究科   創造エネルギー  

  •  
    -
    2001年

    東京工業大学   工学部   機械宇宙工学  

学位

  • 2005年03月   東京工業大学   博士(理学)

所属学協会

  •  
     
     

    Committee on Fluid-Structure Interaction, Applied Mechanics Division, ASME

  •  
     
     

    Journal of Applied Mechanics, ASME

  •  
     
     

    Committee on Fluid-Structure Interaction, Applied Mechanics Division, ASME

  •  
     
     

    Committee on Fluid-Structure Interaction, Applied Mechanics Division, ASME

 

研究分野

  • 流体工学

研究キーワード

  • 構造解析

  • 数値流体力学

  • アイソジオメトリック解析

  • 流体構造連成

論文

  • Anatomically realistic lumen motion representation in patient-specific space-time isogeometric flow analysis of coronary arteries with time-dependent medical-image data

    Yu, Yuxuan, Zhang, Yongjie Jessica, Takizawa, Kenji, Tezduyar, Tayfun E., Sasaki, Takafumi

    COMPUTATIONAL MECHANICS   65 ( 2 ) 395 - 404  2020年02月  [査読有り]

     概要を見る

    Patient-specific computational flow analysis of coronary arteries with time-dependent medical-image data can provide valuable information to doctors making treatment decisions. Reliable computational analysis requires a good core method, high-fidelity space and time discretizations, and an anatomically realistic representation of the lumen motion. The space-time variational multiscale (ST-VMS) method has a good track record as a core method. The ST framework, in a general context, provides higher-order accuracy. The VMS feature of the ST-VMS addresses the computational challenges associated with the multiscale nature of the unsteady flow in the artery. The moving-mesh feature of the ST framework enables high-resolution flow computation near the moving fluid-solid interfaces. The ST isogeometric analysis is a superior discretization method. With IGA basis functions in space, it enables more accurate representation of the lumen geometry and increased accuracy in the flow solution. With IGA basis functions in time, it enables a smoother representation of the lumen motion and a mesh motion consistent with that. With cubic NURBS in time, we obtain a continuous acceleration from the lumen-motion representation. Here we focus on making the lumen-motion representation anatomically realistic. We present a method to obtain from medical-image data in discrete form an anatomically realistic NURBS representation of the lumen motion, without sudden, unrealistic changes introduced by the higher-order representation. In the discrete projection from the medical-image data to the NURBS representation, we supplement the least-squares terms with two penalty terms, corresponding to the first and second time derivatives of the control-point trajectories. The penalty terms help us avoid the sudden unrealistic changes. The computation we present demonstrates the effectiveness of the method.

    DOI

  • Space–Time Variational Multiscale Isogeometric Analysis of a tsunami-shelter vertical-axis wind turbine

    Yuto Otoguro, Hiroki Mochizuki, Kenji Takizawa, Tayfun E. Tezduyar

    Computational Mechanics    2020年

     概要を見る

    © 2020, The Author(s). We present computational flow analysis of a vertical-axis wind turbine (VAWT) that has been proposed to also serve as a tsunami shelter. In addition to the three-blade rotor, the turbine has four support columns at the periphery. The columns support the turbine rotor and the shelter. Computational challenges encountered in flow analysis of wind turbines in general include accurate representation of the turbine geometry, multiscale unsteady flow, and moving-boundary flow associated with the rotor motion. The tsunami-shelter VAWT, because of its rather high geometric complexity, poses the additional challenge of reaching high accuracy in turbine-geometry representation and flow solution when the geometry is so complex. We address the challenges with a space–time (ST) computational method that integrates three special ST methods around the core, ST Variational Multiscale (ST-VMS) method, and mesh generation and improvement methods. The three special methods are the ST Slip Interface (ST-SI) method, ST Isogeometric Analysis (ST-IGA), and the ST/NURBS Mesh Update Method (STNMUM). The ST-discretization feature of the integrated method provides higher-order accuracy compared to standard discretization methods. The VMS feature addresses the computational challenges associated with the multiscale nature of the unsteady flow. The moving-mesh feature of the ST framework enables high-resolution computation near the blades. The ST-SI enables moving-mesh computation of the spinning rotor. The mesh covering the rotor spins with it, and the SI between the spinning mesh and the rest of the mesh accurately connects the two sides of the solution. The ST-IGA enables more accurate representation of the blade and other turbine geometries and increased accuracy in the flow solution. The STNMUM enables exact representation of the mesh rotation. A general-purpose NURBS mesh generation method makes it easier to deal with the complex turbine geometry. The quality of the mesh generated with this method is improved with a mesh relaxation method based on fiber-reinforced hyperelasticity and optimized zero-stress state. We present computations for the 2D and 3D cases. The computations show the effectiveness of our ST and mesh generation and relaxation methods in flow analysis of the tsunami-shelter VAWT.

    DOI

  • ALE and Space–Time Variational Multiscale Isogeometric Analysis of Wind Turbines and Turbomachinery

    Yuri Bazilevs, Kenji Takizawa, Tayfun E. Tezduyar, Ming Chen Hsu, Yuto Otoguro, Hiroki Mochizuki, Michael C.H. Wu

    Modeling and Simulation in Science, Engineering and Technology     195 - 233  2020年

     概要を見る

    © 2020, Springer Nature Switzerland AG. Many of the challenges encountered in computational analysis of wind turbines and turbomachinery are being addressed by the Arbitrary Lagrangian–Eulerian (ALE) and Space–Time (ST) Variational Multiscale (VMS) methods and isogeometric discretization. The computational challenges include turbulent rotational flows, complex geometries, moving boundaries and interfaces, such as the rotor motion, and the fluid–structure interaction (FSI), such as the FSI between the wind turbine blade and the air. The core computational methods are the ALE-VMS and ST-VMS methods. These are supplemented with special methods like the Slip Interface (SI) method and ST Isogeometric Analysis with NURBS basis functions in time. We describe the core and special methods and present, as examples of challenging computations performed, computational analysis of horizontal- and vertical-axis wind turbines and flow-driven string dynamics in pumps.

    DOI

  • Element length calculation in B-spline meshes for complex geometries

    Otoguro, Yuto, Takizawa, Kenji, Tezduyar, Tayfun E.

    COMPUTATIONAL MECHANICS    2020年01月  [査読有り]

     概要を見る

    Variational multiscale methods, and their precursors, stabilized methods, have been playing a core-method role in semi-discrete and space-time (ST) flow computations for decades. These methods are sometimes supplemented with discontinuity-capturing (DC) methods. The stabilization and DC parameters embedded in most of these methods play a significant role. Various well-performing stabilization and DC parameters have been introduced in both the semi-discrete and ST contexts. The parameters almost always involve some element length expressions, most of the time in specific directions, such as the direction of the flow or solution gradient. Until recently, stabilization and DC parameters originally intended for finite element discretization were being used also for isogeometric discretization. Recently, element lengths and stabilization and DC parameters targeting isogeometric discretization were introduced for ST and semi-discrete computations, and these expressions are also applicable to finite element discretization. The key stages of deriving the direction-dependent element length expression were mapping the direction vector from the physical (ST or space-only) element to the parent element in the parametric space, accounting for the discretization spacing along each of the parametric coordinates, and mapping what has been obtained back to the physical element. Targeting B-spline meshes for complex geometries, we introduce here new element length expressions, which are outcome of a clear and convincing derivation and more suitable for element-level evaluation. The new expressions are based on a preferred parametric space and a transformation tensor that represents the relationship between the integration and preferred parametric spaces. The test computations we present for advection-dominated cases, including 2D computations with complex meshes, show that the proposed element length expressions result in good solution profiles.

    DOI

  • Isogeometric hyperelastic shell analysis with out-of-plane deformation mapping (vol 63, pg 681, 2019)

    Takizawa, Kenji, Tezduyar, Tayfun E., Sasaki, Takafumi

    COMPUTATIONAL MECHANICS   65 ( 1 ) 267 - 268  2020年01月  [査読有り]

    DOI

  • A node-numbering-invariant directional length scale for simplex elements

    Takizawa, Kenji, Ueda, Yuki, Tezduyar, Tayfun E.

    MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES   29 ( 14 ) 2719 - 2753  2019年12月  [査読有り]

     概要を見る

    Variational multiscale methods, and their precursors, stabilized methods, have been very popular in flow computations in the past several decades. Stabilization parameters embedded in most of these methods play a significant role. The parameters almost always involve element length scales, most of the time in specific directions, such as the direction of the flow or solution gradient. We require the length scales, including the directional length scales, to have node-numbering invariance for all element types, including simplex elements. We propose a length scale expression meeting that requirement. We analytically evaluate the expression in the context of simplex elements and compared to one of the most widely used length scale expressions and show the levels of noninvariance avoided.

    DOI

  • Space–time computational analysis of tire aerodynamics with actual geometry, road contact, tire deformation, road roughness and fluid film

    Kuraishi T, Takizawa K, Tezduyar T.E

    Computational Mechanics   64 ( 6 ) 1699 - 1718  2019年12月  [査読有り]

    DOI

  • Space–time VMS flow analysis of a turbocharger turbine with isogeometric discretization: computations with time-dependent and steady-inflow representations of the intake/exhaust cycle

    Otoguro Y, Takizawa K, Tezduyar T.E, Nagaoka K, Avsar R, Zhang Y

    Computational Mechanics   64 ( 5 ) 1403 - 1419  2019年11月  [査読有り]

    DOI

  • Computational analysis of performance deterioration of a wind turbine blade strip subjected to environmental erosion

    Castorrini A, Corsini A, Rispoli F, Venturini P, Takizawa K, Tezduyar T.E

    Computational Mechanics   64 ( 4 ) 1133 - 1153  2019年10月  [査読有り]

    DOI

  • Computer Modeling of Wind Turbines: 1. ALE-VMS and ST-VMS Aerodynamic and FSI Analysis

    Korobenko A, Bazilevs Y, Takizawa K, Tezduyar T.E

    Archives of Computational Methods in Engineering   26 ( 4 ) 1059 - 1099  2019年09月  [査読有り]

    DOI

  • Medical-image-based aorta modeling with zero-stress-state estimation

    Sasaki T, Takizawa K, Tezduyar T.E

    Computational Mechanics   64 ( 1 ) 249 - 271  2019年07月  [査読有り]

    DOI

  • Aorta zero-stress state modeling with T-spline discretization

    Sasaki T, Takizawa K, Tezduyar T.E

    Computational Mechanics   63 ( 6 ) 1315 - 1331  2019年06月  [査読有り]

    DOI

  • Tire aerodynamics with actual tire geometry, road contact and tire deformation

    Kuraishi T, Takizawa K, Tezduyar T.E

    Computational Mechanics   63 ( 6 ) 1165 - 1185  2019年06月  [査読有り]

    DOI

  • Computational analysis methods for complex unsteady flow problems

    Bazilevs Y, Takizawa K, Tezduyar T.E

    Mathematical Models and Methods in Applied Sciences   29 ( 5 ) 825 - 838  2019年05月  [査読有り]

    DOI

  • Space-time isogeometric flow analysis with built-in Reynolds-equation limit

    Kuraishi T, Takizawa K, Tezduyar T.E

    Mathematical Models and Methods in Applied Sciences   29 ( 5 ) 871 - 904  2019年05月  [査読有り]

    DOI

  • Methods for computation of flow-driven string dynamics in a pump and residence time

    Kanai T, Takizawa K, Tezduyar T.E, Komiya K, Kaneko M, Hirota K, Nohmi M, Tsuneda T, Kawai M, Isono M

    Mathematical Models and Methods in Applied Sciences   29 ( 5 ) 839 - 870  2019年05月  [査読有り]

    DOI

  • A stabilized ALE method for computational fluid-structure interaction analysis of passive morphing in turbomachinery

    Castorrini A, Corsini A, Rispoli F, Takizawa K, Tezduyar T.E

    Mathematical Models and Methods in Applied Sciences   29 ( 5 ) 967 - 994  2019年05月  [査読有り]

    DOI

  • Space–time computations in practical engineering applications: a summary of the 25-year history

    Tezduyar T.E, Takizawa K

    Computational Mechanics   63 ( 4 ) 747 - 753  2019年04月  [査読有り]

    DOI

  • Isogeometric hyperelastic shell analysis with out-of-plane deformation mapping

    Takizawa K, Tezduyar T.E, Sasaki T

    Computational Mechanics   63 ( 4 ) 681 - 700  2019年04月  [査読有り]

    DOI

  • Compressible-flow geometric-porosity modeling and spacecraft parachute computation with isogeometric discretization

    Kanai T, Takizawa K, Tezduyar T.E, Tanaka T, Hartmann A

    Computational Mechanics   63 ( 2 ) 301 - 321  2019年02月  [査読有り]

    DOI

  • Computational analysis of flow-driven string dynamics in a pump and residence time calculation

    Komiya K, Kanai T, Otoguro Y, Kaneko M, Hirota K, Zhang Y, Takizawa K, Tezduyar T.E, Nohmi M, Tsuneda T, Kawai M, Isono M

    IOP Conference Series: Earth and Environmental Science   240 ( 6 )  2019年  [査読有り]

    DOI

  • Turbocharger turbine and exhaust manifold flow computation with the Space–Time Variational Multiscale Method and Isogeometric Analysis

    Yuto Otoguro, Kenji Takizawa, Tayfun E. Tezduyar, Kenichiro Nagaoka, Sen Mei

    Computers & Fluids   179   766 - 778  2019年01月  [査読有り]

    DOI

  • Mesh refinement influence and cardiac-cycle flow periodicity in aorta flow analysis with isogeometric discretization

    Kenji Takizawa, Tayfun E. Tezduyar, Hiroaki Uchikawa, Takuya Terahara, Takafumi Sasaki, Ayaka Yoshida

    Computers & Fluids   179   792 - 800  2019年01月  [査読有り]

    DOI

  • Stabilization and discontinuity-capturing parameters for space–time flow computations with finite element and isogeometric discretizations

    Takizawa K, Tezduyar T.E, Otoguro Y

    Computational Mechanics   62 ( 5 ) 1169 - 1186  2018年11月  [査読有り]

    DOI

  • Space–Time computational analysis of tire aerodynamics with actual geometry, road contact, and tire deformation

    Kuraishi T, Takizawa K, Tezduyar T.E

    Modeling and Simulation in Science, Engineering and Technology     337 - 376  2018年  [査読有り]

    DOI

  • Recent advances in ALE-VMS and ST-VMS computational aerodynamic and FSI analysis of wind turbines

    Korobenko A, Bazilevs Y, Takizawa K, Tezduyar T.E

    Modeling and Simulation in Science, Engineering and Technology     253 - 336  2018年  [査読有り]

    DOI

  • Aorta flow analysis and heart valve flow and structure analysis

    Takizawa K, Tezduyar T.E, Uchikawa H, Terahara T, Sasaki T, Shiozaki K, Yoshida A, Komiya K, Inoue G

    Modeling and Simulation in Science, Engineering and Technology     29 - 89  2018年  [査読有り]

    DOI

  • A general-purpose NURBS mesh generation method for complex geometries

    Otoguro Y, Takizawa K, Tezduyar T.E

    Modeling and Simulation in Science, Engineering and Technology     399 - 434  2018年  [査読有り]

    DOI

  • Heart valve flow computation with the space-time slip interface topology change (ST-SI-TC) method and isogeometric analysis (IGA)

    Kenji Takizawa, Tayfun E. Tezduyar, Takuya Terahara, Takafumi Sasaki

    Lecture Notes in Applied and Computational Mechanics   84   77 - 99  2018年  [査読有り]

     概要を見る

    We present a heart valve flow computation with the Space-Time Slip Interface Topology Change (ST-SI-TC) method and Isogeometric Analysis (IGA). The computation is for a realistic heart valve model with actual contact between the valve leaflets. The ST-SI-TC method integrates the ST-SI and ST-TC methods in the framework of the ST Variational Multiscale (ST-VMS) method. The STVMS method functions as a moving-mesh method, which maintains high-resolution boundary layer representation near the solid surfaces. The ST-TC method was introduced for moving-mesh computation of flow problems with TC, such as contact between the leaflets of a heart valve. It deals with the contact while maintaining highresolution representation near the leaflet surfaces. The ST-SI method was originally introduced to addresses the challenge involved in high-resolution representation of the boundary layers near spinning solid surfaces. The mesh covering a spinning solid surface spins with it, and the SI between that mesh and the rest of the mesh accurately connects the two sides. This maintains the high-resolution representation near solid surfaces. In the context of heart valves, the SI connects the sectors of meshes containing the leaflets, enabling a more effective mesh moving. In that context, the ST-SI-TC method enables high-resolution representation even when the contact is between leaflets that are covered by meshes with SI. It also enables dealing with contact location change or contact and sliding on the SI. With IGA, in addition to having a more accurate representation of the surfaces and increased accuracy in the flow solution, the element density in the narrow spaces near the contact areas is kept at a reasonable level. Furthermore, because the flow representation in the contact area has a wider support in IGA, the flow computation method becomes more robust. The computation we present for an aortic-valve model shows the effectiveness of the ST-SI-TC-IGA method.

    DOI

  • Estimation of element-based zero-stress state in arterial FSI computations with isogeometric wall discretization

    Kenji Takizawa, Tayfun E. Tezduyar, Takafumi Sasaki

    Lecture Notes in Applied and Computational Mechanics   84   101 - 122  2018年  [査読有り]

     概要を見る

    In patient-specific arterial fluid-structure interaction computations the image-based arterial geometry does not come from a zero-stress state (ZSS), requiring an estimation of the ZSS. A method for estimation of element-based ZSS (EBZSS) was introduced earlier in the context of finite element wall discretization. The method has three main components. 1. An iterative method, which starts with a calculated initial guess, is used for computing the EBZSS such that when a given pressure load is applied, the image-based target shape is matched. 2. A method for straight-tube segments is used for computing the EBZSS so that we match the given diameter and longitudinal stretch in the target configuration and the “opening angle.” 3. An element-based mapping between the artery and straight-tube is extracted from the mapping between the artery and straight-tube segments. This provides the mapping from the arterial configuration to the straight-tube configuration, and from the estimated EBZSS of the straight-tube configuration back to the arterial configuration, to be used as the initial guess for the iterative method that matches the image-based target shape. Here we introduce the version of the EBZSS estimation method with isogeometric wall discretization. With NURBS basis functions, we may be able to use larger elements, consequently less number of elements, compared to linear basis functions. Higher-order NURBS basis functions allow representation of more complex shapes within an element. To show how the new EBZSS estimation method performs, we present 2D test computations with straight-tube configurations.

    DOI

  • Space–time VMS computational flow analysis with isogeometric discretization and a general-purpose NURBS mesh generation method

    Otoguro Y, Takizawa K, Tezduyar T.E

    Computers and Fluids   158   189 - 200  2017年11月  [査読有り]

    DOI

  • Heart valve flow computation with the integrated Space–Time VMS, Slip Interface, Topology Change and Isogeometric Discretization methods

    Takizawa K, Tezduyar T.E, Terahara T, Sasaki T

    Computers and Fluids   158   176 - 188  2017年11月  [査読有り]

    DOI

  • Porosity models and computational methods for compressible-flow aerodynamics of parachutes with geometric porosity

    Takizawa K, Tezduyar T.E, Kanai T

    Mathematical Models and Methods in Applied Sciences   27 ( 4 ) 771 - 806  2017年04月  [査読有り]

    DOI

  • Aorta modeling with the element-based zero-stress state and isogeometric discretization

    Takizawa K, Tezduyar T.E, Sasaki T

    Computational Mechanics   59 ( 2 ) 265 - 280  2017年02月  [査読有り]

    DOI

  • 宇宙船用パラシュートの数値解析と圧縮性領域への拡張

    滝沢 研二, TEZDUYAR Tayfun E., 金井 太郎

    日本航空宇宙学会誌   65 ( 9 ) 280 - 283  2017年

     概要を見る

    <p>宇宙船用の大型パラシュートの解析は,space-time(ST)法によって信頼できるレベルに達している.大型パラシュート解析は,数値解析において最も難しい課題の一つと言え,その難しさの理由の主なものは,パラシュート自身の大きさに起因している.リングセールパラシュートは,数百の隙間を有し,複雑な形状となることもその一つである.さらに,一部のセールを取り除き,"窓"を作るなど,デザインの柔軟さも解析側からは,難しい点となっている.また,クラスターパラシュートの接触,オープニングステージのリーフィング,その後,段階的に開くという使用コンディションも複雑である.圧縮性領域でのパラシュート解析は,さらなる難しさを加える.パラシュート表面の多孔性そして,複雑形状時の狭い隙間の作る幾何学的多孔性をモデリングすることもその一つである.本記事では,ST法における,多孔性モデルの扱いについても言及する.</p>

    DOI CiNii

  • Finite elements in flow problems 2015, Taiwan

    Lin C.-A, Bazilevs Y, Brummelen E.H, Chen C.-Y, Takizawa K

    Computers and Fluids   142   1 - 2  2017年01月  [査読有り]

    DOI

  • Turbocharger flow computations with the Space–Time Isogeometric Analysis (ST-IGA)

    Kenji Takizawa, Tayfun E. Tezduyar, Yuto Otoguro, Takuya Terahara, Takashi Kuraishi, Hitoshi Hattori

    Computers & Fluids   142   15 - 20  2017年01月  [査読有り]

    DOI

  • Computational analysis of flow-driven string dynamics in turbomachinery

    Kenji Takizawa, Tayfun E. Tezduyar, Hitoshi Hattori

    Computers & Fluids   142   109 - 117  2017年01月  [査読有り]

    DOI

  • Space–Time method for flow computations with slip interfaces and topology changes (ST-SI-TC)

    Takizawa K, Tezduyar T.E, Asada S, Kuraishi T

    Computers and Fluids   141   124 - 134  2016年12月  [査読有り]

    DOI

  • Ram-air parachute structural and fluid mechanics computations with the Space–Time Isogeometric Analysis (ST-IGA)

    Takizawa K, Tezduyar T.E, Terahara T

    Computers and Fluids   141   191 - 200  2016年12月  [査読有り]

    DOI

  • Computational analysis of wind-turbine blade rain erosion

    Castorrini A, Corsini A, Rispoli F, Venturini P, Takizawa K, Tezduyar T.E

    Computers and Fluids   141   175 - 183  2016年12月  [査読有り]

    DOI

  • Computational Fluid–Structure Interaction and Flow Simulation

    Bazilevs Y, Takizawa K

    Computers and Fluids   141   1 - 1  2016年12月  [査読有り]

    DOI

  • Preface

    Chris Biemann, Andre Freitas, Siegfried Handschuh, Elisabeth Metais, Farid Meziane

    DATA & KNOWLEDGE ENGINEERING   106   36 - 37  2016年11月  [査読有り]

    DOI

  • Finite elements in flow problems 2015

    Chao-An Lin

    COMPUTERS & MATHEMATICS WITH APPLICATIONS   72 ( 8 ) 1957 - 1958  2016年10月  [査読有り]

    DOI

  • Computational thermo-fluid analysis of a disk brake

    Takizawa K, Tezduyar T.E, Kuraishi T, Tabata S, Takagi H

    Computational Mechanics   57 ( 6 ) 965 - 977  2016年06月  [査読有り]

    DOI

  • SUPG/PSPG computational analysis of rain erosion in wind-turbine blades

    Alessio Castorrini, Alessandro Corsini, Franco Rispoli, Paolo Venturini, Kenji Takizawa, Tayfun E. Tezduyar

    Modeling and Simulation in Science, Engineering and Technology     77 - 96  2016年  [査読有り]

     概要を見る

    Wind-turbine blades exposed to rain can be damaged by erosion if not protected. Although this damage does not typically influence the structural response of the blades,it could heavily degrade the aerodynamic performance,and therefore the power production. We present a method for computational analysis of rain erosion in wind-turbine blades. The method is based on a stabilized finite element fluid mechanics formulation and a finite element particle-cloud tracking method. Accurate representation of the flow would be essential in reliable computational turbomachinery analysis and design. The turbulent-flow nature of the problem is dealt with a RANS model and SUPG/PSPG stabilization,the particle-cloud trajectories are calculated based on the flow field and closure models for the turbulence-particle interaction,and one-way dependence is assumed between the flow field and particle dynamics. The erosion patterns are then computed based on the particle-cloud data.

    DOI

  • New directions in space-time computational methods

    Kenji Takizawa, Tayfun E. Tezduyar

    Modeling and Simulation in Science, Engineering and Technology     159 - 178  2016年  [査読有り]

     概要を見る

    This is an overview of some of the new directions we have taken the space-time (ST) computational methods since 2010 in bringing solution and analysis to different classes of challenging engineering problems. The new directions include the variational multiscale (VMS) version of the Deforming-Spatial-Domain/Stabilized ST method,using NURBS basis functions in temporal representation of the unknown variables and motion of the solid surfaces and fluid mechanics meshes,ST techniques with continuous representation in time,ST interface-tracking with topology change,and the ST-VMS method for flow computations with slip interfaces. We describe these new directions and present a few examples.

    DOI

  • A geometrical-characteristics study in patient-specific FSI analysis of blood flow in the thoracic aorta

    Hiroshi Suito, Kenji Takizawa, Viet Q. H. Huynh, Daniel Sze, Takuya Ueda, Tayfun E. Tezduyar

    Modeling and Simulation in Science, Engineering and Technology     379 - 386  2016年  [査読有り]

     概要を見る

    This chapter is on fluid-structure interaction (FSI) analysis of blood flow in the thoracic aorta. The FSI is handled with the Sequentially Coupled Arterial FSI technique. We focus on the relationship between the aorta centerline geometry and the wall shear stress (WSS) distribution. The model centerlines are extracted from the CT scans,and we assume a constant diameter for the artery segment. Then,torsion-free model geometries are generated by projecting the original centerline to its averaged plane of curvature. The WSS distributions for the original and projected geometries are compared to examine the influence of the torsion.

    DOI

  • Space-time VMS method for flow computations with slip interfaces (ST-SI)

    Takizawa K, Tezduyar T.E, Mochizuki H, Hattori H, Mei S, Pan L, Montel K

    Mathematical Models and Methods in Applied Sciences   25 ( 12 ) 2377 - 2406  2015年11月  [査読有り]

    DOI

  • New directions and challenging computations in fluid dynamics modeling with stabilized and multiscale methods

    Bazilevs Yuri, Takizawa Kenji, Tezduyar Tayfun E

    Mathematical Models & Methods in Applied Sciences   25 ( 12 ) 2217 - 2226  2015年11月  [査読有り]

    DOI

  • Multiscale space-time methods for thermo-fluid analysis of a ground vehicle and its tires

    Takizawa Kenji, Tezduyar Tayfun E, Kuraishi Takashi

    Mathematical Models & Methods in Applied Sciences   25 ( 12 ) 2227 - 2255  2015年11月  [査読有り]

    DOI

  • Special methods for aerodynamic-moment calculations from parachute FSI modeling

    Takizawa K, Tezduyar T.E, Boswell C, Tsutsui Y, Montel K

    Computational Mechanics   55 ( 6 ) 1059 - 1069  2015年06月  [査読有り]

    DOI

  • Space-time computational analysis of MAV flapping-wing aerodynamics with wing clapping

    Takizawa Kenji, Tezduyar Tayfun E, Buscher Austin

    Computational Mechanics   55 ( 6 ) 1131 - 1141  2015年06月  [査読有り]

    DOI

  • Fluid-structure interaction

    Bazilevs Yuri, Takizawa Kenji, Tezduyar Tayfun E

    Computational Mechanics   55 ( 6 ) 1057 - 1058  2015年06月  [査読有り]

    DOI

  • FSI modeling of the Orion spacecraft drogue parachutes

    Takizawa Kenji, Tezduyar Tayfun E, Kolesar Ryan

    Computational Mechanics   55 ( 6 ) 1167 - 1179  2015年06月  [査読有り]

    DOI

  • Multiscale space-time methods for thermo-fluid analysis of a ground vehicle and its tires

    Takizawa K, Tezduyar T.E, Kuraishi T

    Mathematical Models and Methods in Applied Sciences   25 ( 12 ) 2227 - 2255  2015年  [査読有り]

    DOI

  • Multiscale methods for gore curvature calculations from FSI modeling of spacecraft parachutes

    Takizawa Kenji, Tezduyar Tayfun E, Kolesar Ryan, Boswell Cody, Kanai Taro, Montel Kenneth

    Computational Mechanics   54 ( 6 ) 1461 - 1476  2014年12月  [査読有り]

    DOI

  • Engineering Analysis and Design with ALE-VMS and Space-Time Methods

    Takizawa Kenji, Bazilevs Yuri, Tezduyar Tayfun E, Hsu Ming-Chen, Oiseth Ole, Mathisen Kjell M, Kostov Nikolay, McIntyre Spenser

    Archives of Computational Methods in Engineering   21 ( 4 ) 481 - 508  2014年12月  [査読有り]

    DOI

  • Aerodynamic and FSI Analysis of Wind Turbines with the ALE-VMS and ST-VMS Methods

    Bazilevs Y, Takizawa K, Tezduyar T.E, Hsu M.-C, Kostov N, McIntyre S

    Archives of Computational Methods in Engineering   21 ( 4 ) 359 - 398  2014年12月  [査読有り]

    DOI

  • ST and ALE-VMS methods for patient-specific cardiovascular fluid mechanics modeling

    Takizawa K, Bazilevs Y, Tezduyar T. E, Long C. C, Marsden A. L, Schjodt K

    Mathematical Models & Methods in Applied Sciences   24 ( 12 ) 50  2014年11月  [査読有り]

    DOI

  • FSI modeling of the reefed stages and disreefing of the Orion spacecraft parachutes

    Takizawa Kenji, Tezduyar Tayfun E, Boswell Cody, Kolesar Ryan, Montel Kenneth

    Computational Mechanics   54 ( 5 ) 1203 - 1220  2014年11月  [査読有り]

    DOI

  • A variational multiscale method for particle-cloud tracking in turbomachinery flows

    A. Corsini, F. Rispoli, A. G. Sheard, K. Takizawa, T. E. Tezduyar, P. Venturini

    COMPUTATIONAL MECHANICS   54 ( 5 ) 1191 - 1202  2014年11月  [査読有り]

     概要を見る

    We present a computational method for simulation of particle-laden flows in turbomachinery. The method is based on a stabilized finite element fluid mechanics formulation and a finite element particle-cloud tracking method. We focus on induced-draft fans used in process industries to extract exhaust gases in the form of a two-phase fluid with a dispersed solid phase. The particle-laden flow causes material wear on the fan blades, degrading their aerodynamic performance, and therefore accurate simulation of the flow would be essential in reliable computational turbomachinery analysis and design. The turbulent-flow nature of the problem is dealt with a Reynolds-Averaged Navier-Stokes model and Streamline-Upwind/Petrov-Galerkin/Pressure-Stabilizing/Petrov-Galerkin stabilization, the particle-cloud trajectories are calculated based on the flow field and closure models for the turbulence-particle interaction, and one-way dependence is assumed between the flow field and particle dynamics. We propose a closure model utilizing the scale separation feature of the variational multiscale method, and compare that to the closure utilizing the eddy viscosity model. We present computations for axial- and centrifugal-fan configurations, and compare the computed data to those obtained from experiments, analytical approaches, and other computational methods.

    DOI

  • Space-time interface-tracking with topology change (ST-TC)

    Takizawa Kenji, Tezduyar Tayfun E, Buscher Austin, Asada Shohei

    Computational Mechanics   54 ( 4 ) 955 - 971  2014年10月  [査読有り]

    DOI

  • Space-time fluid mechanics computation of heart valve models

    Takizawa Kenji, Tezduyar Tayfun E, Buscher Austin, Asada Shohei

    Computational Mechanics   54 ( 4 ) 973 - 986  2014年10月  [査読有り]

    DOI

  • FSI analysis of the blood flow and geometrical characteristics in the thoracic aorta

    Suito H, Takizawa K, Huynh V.Q.H, Sze D, Ueda T

    Computational Mechanics   54 ( 4 ) 1035 - 1045  2014年10月  [査読有り]

    DOI

  • Estimation of element-based zero-stress state for arterial FSI computations

    Takizawa Kenji, Takagi Hirokazu, Tezduyar Tayfun E, Torii Ryo

    Computational Mechanics   54 ( 4 ) 895 - 910  2014年10月  [査読有り]

    DOI

  • Coronary arterial dynamics computation with medical-image-based time-dependent anatomical models and element-based zero-stress state estimates

    Takizawa Kenji, Torii Ryo, Takagi Hirokazu, Tezduyar Tayfun E, Xu Xiao Y

    Computational Mechanics   54 ( 4 ) 1047 - 1053  2014年10月  [査読有り]

    DOI

  • Biomedical fluid mechanics and fluid-structure interaction

    Bazilevs Yuri, Takizawa Kenji, Tezduyar Tayfun E

    Computational Mechanics   54 ( 4 ) 893 - 893  2014年10月  [査読有り]

    DOI

  • Sequentially-coupled space-time FSI analysis of bio-inspired flapping-wing aerodynamics of an MAV

    Takizawa K, Tezduyar T.E, Kostov N

    Computational Mechanics   54 ( 2 ) 213 - 233  2014年08月  [査読有り]

    DOI

  • Computational engineering analysis with the new-generation space-time methods

    Takizawa Kenji

    Computational Mechanics   54 ( 2 ) 193 - 211  2014年08月  [査読有り]

    DOI

  • 固体表面間摩擦モデルの基礎検討

    岡田 尚也, 川井 政人, 滝沢 研二, 服部 均, Tezduyar Tayfun, 宮川 和芳, 斎藤 純夫, 磯野 美帆, 能見 基彦, 打田 博

    理論応用力学講演会 講演論文集   63 ( 0 ) 86 - 86  2014年

     概要を見る

    汚水ポンプでは、流れてきたタオルやおむつなどの異物が内部で回転する羽に絡まる<br>場合があり、故障の原因となる。本研究では羽まわりの流体および異物の数値解析を行<br>うことで物が後流に通過する指標を考案し、ポンプ開発の設計支援を行うことを目的と<br>する。<br>基礎検討として、空気管路内に設けた障害物と紐との接触時に発生する摩擦力の大き<br>さを求めるための実験を行う。また、実験より摩擦モデルを構築し、その諸係数を測定<br>する。最後に本モデルを用い、数値解析により紐の運動を計算し、実験との比較するこ<br>とでモデルの確からしさを検証する。

    DOI CiNii

  • Space-time computation techniques with continuous representation in time (ST-C)

    Takizawa K, Tezduyar T.E

    Computational Mechanics   53 ( 1 ) 91 - 99  2014年01月  [査読有り]

    DOI

  • Space-time VMS computation of wind-turbine rotor and tower aerodynamics

    Takizawa K, Tezduyar T.E, McIntyre S, Kostov N, Kolesar R, Habluetzel C

    Computational Mechanics   53 ( 1 ) 1 - 15  2014年01月  [査読有り]

    DOI

  • ST and ALE-VMS methods for patient-specific cardiovascular fluid mechanics modeling

    Kenji Takizawa, Yuri Bazilevs, Tayfun E. Tezduyar, Christopher C. Long, Alison L. Marsden, Kathleen Schjodt

    Mathematical Models and Methods in Applied Sciences   24 ( 12 ) 2437 - 2486  2014年  [査読有り]

     概要を見る

    This paper provides a review of the space-time (ST) and Arbitrary Lagrangian-Eulerian (ALE) techniques developed by the first three authors' research teams for patient-specific cardiovascular fluid mechanics modeling, including fluid-structure interaction (FSI). The core methods are the ALE-based variational multiscale (ALE-VMS) method, the Deforming-Spatial-Domain/Stabilized ST formulation, and the stabilized ST FSI technique. A good number of special techniques targeting cardiovascular fluid mechanics have been developed to be used with the core methods. These include: (i) arterial-surface extraction and boundary condition techniques, (ii) techniques for using variable arterial wall thickness, (iii) methods for calculating an estimated zero-pressure arterial geometry, (iv) techniques for prestressing of the blood vessel wall, (v) mesh generation techniques for building layers of refined fluid mechanics mesh near the arterial walls, (vi) a special mapping technique for specifying the velocity profile at an inflow boundary with non-circular shape, (vii) a scaling technique for specifying a more realistic volumetric flow rate, (viii) techniques for the projection of fluid-structure interface stresses, (ix) a recipe for pre-FSI computations that improve the convergence of the FSI computations, (x) the Sequentially-Coupled Arterial FSI technique and its multiscale versions, (xi) techniques for calculation of the wall shear stress (WSS) and oscillatory shear index (OSI), (xii) methods for stent modeling and mesh generation, (xiii) methods for calculation of the particle residence time, and (xiv) methods for an estimated element-based zero-stress state for the artery. Here we provide an overview of the special techniques for WSS and OSI calculations, stent modeling and mesh generation, and calculation of the residence time with application to pulsatile ventricular assist device (PVAD). We provide references for some of the other special techniques. With results from earlier computations, we show how these core and special techniques work. © 2014 World Scientific Publishing Company.

    DOI

  • Patient-specific cardiovascular fluid mechanics analysis with the ST and ALE-VMS methods

    Kenji Takizawa, Yuri Bazilevs, Tayfun E. Tezduyar, Christopher C. Long, Alison L. Marsden, Kathleen Schjodt

    Computational Methods in Applied Sciences   33   71 - 102  2014年  [査読有り]

     概要を見る

    This chapter provides an overview of how patient-specific cardiovascular fluid mechanics analysis, including fluid-structure interaction (FSI), can be carried out with the space-time (ST) and Arbitrary Lagrangian-Eulerian (ALE) techniques developed by the first three authors' research teams. The core methods are the ALE-based variational multiscale (ALE-VMS) method, the Deforming-Spatial-Domain/Stabilized ST formulation, and the stabilized ST FSI technique. A good number of special techniques targeting cardiovascular fluid mechanics have been developed to be used with the coremethods. These include (i) arterial-surface extraction and boundary condition techniques, (ii) techniques for using variable arterialwall thickness, (iii) methods for calculating an estimated zero-pressure arterial geometry, (iv) techniques for prestressing of the blood vessel wall, (v) mesh generation techniques for building layers of refined fluid mechanics mesh near the arterial walls, (vi) a special mapping technique for specifying the velocity profile at an inflow boundary with non-circular shape, (vii) a scaling technique for specifying a more realistic volumetric flow rate, (viii) techniques for the projection of fluid-structure interface stresses, (ix) a recipe for pre-FSI computations that improve the convergence of the FSI computations, (x) the Sequentially-Coupled Arterial FSI technique and its multiscale versions, (xi) techniques for calculation of the wall shear stress (WSS) and oscillatory shear index (OSI), (xii) methods for stent modeling and mesh generation, (xiii) methods for calculation of the particle residence time, and (xiv) methods for an estimated element-based zero-stress state for the artery. Here we provide an overview of the special techniques for stent modeling and mesh generation and calculation of the residence time with application to pulsatile ventricular assist device (PVAD). We provide references for some of the other special techniques. With results from earlier computations, we show how the core and special techniques work.

    DOI

  • Fluid–structure interaction modeling of patient-specific cerebral aneurysms

    Takizawa K, Tezduyar T.E

    Lecture Notes in Computational Vision and Biomechanics   12   25 - 45  2014年  [査読有り]

    DOI

  • Computational wind-turbine analysis with the ALE-VMS and ST-VMS methods

    Yuri Bazilevs, Kenji Takizawa, Tayfun E. Tezduyar, Ming-Chen Hsu, Nikolay Kostov, Spenser McIntyre

    Computational Methods in Applied Sciences   33   355 - 386  2014年  [査読有り]

     概要を見る

    We provide an overview of the aerodynamic and FSI analysis of wind turbines the first three authors' teams carried out in recent years with the ALE-VMS and ST-VMS methods. The ALE-VMS method is the variational multiscale version of the Arbitrary Lagrangian-Eulerian (ALE) method. The VMS components are from the residual-based VMS (RBVMS) method. The ST-VMS method is the VMS version of the Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) method. The techniques complementing these core methods include weak enforcement of the essential boundary conditions, NURBS-based isogeometric analysis, using NURBS basis functions in temporal representation of the rotor motion, mesh motion and also in remeshing, rotation representation with constant angular velocity, Kirchhoff-Love shell modeling of the rotor-blade structure, and full FSI coupling. The analysis cases include the aerodynamics of wind-turbine rotor and tower and the FSI that accounts for the deformation of the rotor blades. The specific wind turbines considered are NREL 5MW, NREL Phase VI and Micon 65/13M, all at full scale, and our analysis for NREL Phase VI and Micon 65/13M includes comparison with the experimental data.

    DOI

  • Computational engineering analysis and design with ALE-VMS and ST methods

    Kenji Takizawa, Yuri Bazilevs, Tayfun E. Tezduyar, Ming-Chen Hsu, Ole Øiseth, Kjell M. Mathisen, Nikolay Kostov, Spenser McIntyre

    Computational Methods in Applied Sciences   33   321 - 353  2014年  [査読有り]

     概要を見る

    Flows with moving interfaces include fluid-structure interaction (FSI) and quite a few other classes of problems, have an important place in engineering analysis and design, and pose significant computational challenges. Bringing solution and analysis to them motivated the Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) method and also the variational multiscale version of the Arbitrary Lagrangian-Eulerian method (ALE-VMS). These two methods and their improved versions have been applied to a diverse set of challenging problems with a common core computational technology need. The classes of problems solved include free-surface and two-fluid flows, fluid-object and fluid-particle interaction, FSI, and flows with solid surfaces in fast, linear or rotational relative motion. Some of the most challenging FSI problems, including parachute FSI, wind-turbine FSI and arterial FSI, are being solved and analyzed with the DSD/SST and ALE-VMS methods as core technologies. Better accuracy and improved turbulence modeling were brought with the recently-introduced VMS version of the DSD/SST method, which is called DSD/SST-VMST (also ST-VMS). In specific classes of problems, such as parachute FSI, arterial FSI, ship hydrodynamics, fluid-object interaction, aerodynamics of flapping wings, and wind-turbine aerodynamics and FSI, the scope and accuracy of the modeling were increased with the special ALE-VMS and ST techniques targeting each of those classes of problems. This article provides an overview of how the core and special ALE-VMS and ST techniques are used in computational engineering analysis and design. The article includes an overview of three of the special ALE-VMS and ST techniques, which are just a few examples of the many special techniques that complement the core methods. The impact of the ALE-VMS and ST methods in engineering analysis and design are shown with examples of challenging problems solved and analyzed in parachute FSI, arterial FSI, ship hydrodynamics, aerodynamics of flapping wings, wind-turbine aerodynamics, and bridge-deck aerodynamics and vortex-induced vibrations.

    DOI

  • Fluid-structure interaction modeling of clusters of spacecraft parachutes with modified geometric porosity

    Takizawa K, Tezduyar T.E, Boben J, Kostov N, Boswell C, Buscher A

    Computational Mechanics   52 ( 6 ) 1351 - 1364  2013年12月  [査読有り]

    DOI

  • Computer modeling techniques for flapping-wing aerodynamics of a locust

    Takizawa K, Henicke B, Puntel A, Kostov N, Tezduyar T.E

    Computers and Fluids   85   125 - 134  2013年10月  [査読有り]

    DOI

  • Patient-specific computational analysis of the influence of a stent on the unsteady flow in cerebral aneurysms

    Takizawa K, Schjodt K, Puntel A, Kostov N, Tezduyar T

    Computational Mechanics   51 ( 6 ) 1061 - 1073  2013年06月  [査読有り]

    DOI

  • Patient-Specific Computational Fluid Mechanics of Cerebral Arteries with Aneurysm and Stent

    Kenji Takizawa, Kathleen Schjodt, Anthony Puntel, Nikolay Kostov, Tayfun E. Tezduyar

    Multiscale Simulations and Mechanics of Biological Materials     119 - 147  2013年03月  [査読有り]

     概要を見る

    We present patient-specific computational fluid mechanics analysis of blood flow in cerebral arteries with aneurysm and stent. The special arterial fluid mechanics techniques we have developed for this are used in conjunction with the core computational technique, which is the space-time version of the variational multiscale (VMS) method and is called "DST/SST-VMST." The special techniques include using a nonuniform rational basis spline for the spatial representation of the surface over which the stent mesh is built, mesh generation techniques for both the finite- and zero-thickness representations of the stent, techniques for generating refined layers of mesh near the arterial and stent surfaces, and models for representing double stents. We compute the unsteady flow patterns in the aneurysm and investigate how those patterns are influenced by the presence of single and double stents. We also compare the flow patterns obtained with the finite- and zero-thickness representations of the stent. This edition first published 2013 © 2013 John Wiley &amp
    Sons, Ltd.

    DOI

  • Space-time VMS methods for modeling of incompressible flows at high reynolds numbers

    Kenji Takizawa, Darren Montes, Spenser McIntyre, Tayfun E. Tezduyar

    Mathematical Models and Methods in Applied Sciences   23 ( 2 ) 223 - 248  2013年02月  [査読有り]

     概要を見る

    Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) formulation was developed for flow problems with moving interfaces and has been successfully applied to some of the most complex problems in that category. A new version of the DSD/SST method for incompressible flows, which has additional subgrid-scale representation features, is the space-time version of the residual-based variational multiscale (VMS) method. This new version, called DSD/SST-VMST and also Space-Time VMS (ST-VMS), provides a more comprehensive framework for the VMS method. We describe the ST-VMS method, including the embedded stabilization parameters, and assess its performance in computation of flow problems at high Reynolds numbers by comparing the results to experimental data. The computations, which include those with 3D airfoil geometries and spacecraft configurations, signal a promising future for the ST-VMS method. © 2013 World Scientific Publishing Company.

    DOI

  • METHODS FOR FSI MODELING OF SPACECRAFT PARACHUTE DYNAMICS AND COVER SEPARATION

    Takizawa K, Montes D, Fritze M, McIntyre S, Boben J, Tezduyar T. E

    Mathematical Models & Methods in Applied Sciences   23 ( 2 ) 32  2013年02月  [査読有り]

    DOI

  • Challenges and directions in computational fluid-structure interaction

    Yuri Bazilevs, Kenji Takizawa, Tayfun E. Tezduyar

    Mathematical Models and Methods in Applied Sciences   23 ( 2 ) 215 - 221  2013年02月  [査読有り]

     概要を見る

    In this lead paper of the special issue, we provide some comments on challenges and directions in computational fluid-structure interaction (FSI). We briefly discuss the significance of computational FSI methods, their components, moving-mesh and nonmoving-mesh methods, mesh moving and remeshing concepts, and FSI coupling techniques. © 2013 World Scientific Publishing Company.

    DOI

  • SPACE-TIME VMS METHODS FOR MODELING OF INCOMPRESSIBLE FLOWS AT HIGH REYNOLDS NUMBERS

    Takizawa K, Montes D, McIntyre S, Tezduyar T. E

    Mathematical Models & Methods in Applied Sciences   23 ( 2 ) 26 - 248  2013年02月  [査読有り]

    DOI

  • Methods for FSI modeling of spacecraft parachute dynamics and cover separation

    Kenji Takizawa, Darren Montes, Matthew Fritze, Spenser McIntyre, Joseph Boben, Tayfun E. Tezduyar

    Mathematical Models and Methods in Applied Sciences   23 ( 2 ) 307 - 338  2013年02月  [査読有り]

     概要を見る

    Fluid-structure interaction (FSI) modeling of spacecraft parachutes involves a number of computational challenges beyond those encountered in a typical FSI problem. The stabilized space-time FSI (SSTFSI) technique serves as a robust and accurate core FSI method, and a number of special FSI methods address the computational challenges specific to spacecraft parachutes. Some spacecraft FSI problems involve even more specific computational challenges and require additional special methods. An example of that is the impulse ejection and parachute extraction of a protective cover used in a spacecraft. The computational challenges specific to this problem are related to the sudden changes in the parachute loads and sudden separation of the cover with very little initial clearance from the spacecraft. We describe the core and special FSI methods, and present the methods we use in FSI analysis of the parachute dynamics and cover separation, including the temporal NURBS representation in modeling the separation motion. © 2013 World Scientific Publishing Company.

    DOI

  • CHALLENGES AND DIRECTIONS IN COMPUTATIONAL FLUID-STRUCTURE INTERACTION

    Bazilevs Y, Takizawa K, Tezduyar T. E

    Mathematical Models & Methods in Applied Sciences   23 ( 2 ) 7 - 221  2013年02月  [査読有り]

    DOI

  • Computational Fluid-Structure Interaction: Methods and Applications

    Bazilevs Yuri, Takizawa Kenji, Tezduyar Tayfun E

       2013年  [査読有り]

  • Computational Fluid-Structure Interaction: Methods and Applications

    Yuri Bazilevs, Kenji Takizawa, Tayfun E. Tezduyar

    Computational Fluid-Structure Interaction: Methods and Applications    2012年12月  [査読有り]

     概要を見る

    Computational Fluid-Structure Interaction: Methods and Applications takes the reader from the fundamentals of computational fluid and solid mechanics to the state-of-the-art in computational FSI methods, special FSI techniques, and solution of real-world problems. Leading experts in the field present the material using a unique approach that combines advanced methods, special techniques, and challenging applications. This book begins with the differential equations governing the fluid and solid mechanics, coupling conditions at the fluid-solid interface, and the basics of the finite element method. It continues with the ALE and space-time FSI methods, spatial discretization and time integration strategies for the coupled FSI equations, solution techniques for the fully-discretized coupled equations, and advanced FSI and space-time methods. It ends with special FSI techniques targeting cardiovascular FSI, parachute FSI, and wind-turbine aerodynamics and FSI. Key features: First book to address the state-of-the-art in computational FSI Combines the fundamentals of computational fluid and solid mechanics, the state-of-the-art in FSI methods, and special FSI techniques targeting challenging classes of real-world problems Covers modern computational mechanics techniques, including stabilized, variational multiscale, and space-time methods, isogeometric analysis, and advanced FSI coupling methods. Is in full color, with diagrams illustrating the fundamental concepts and advanced methods and with insightful visualization illustrating the complexities of the problems that can be solved with the FSI methods covered in the book. Authors are award winning, leading global experts in computational FSI, who are known for solving some of the most challenging FSI problems. Computational Fluid-Structure Interaction: Methods and Applications is a comprehensive reference for researchers and practicing engineers who would like to advance their existing knowledge on these subjects. It is also an ideal text for graduate and senior-level undergraduate courses in computational fluid mechanics and computational FSI. © 2013 John Wiley &amp
    Sons, Ltd.

    DOI

  • bringing them down safely

    Takizawa K, Tezduyar T. E

    Mechanical Engineering   134 ( 12 ) 34 - 37  2012年12月  [査読有り]

    DOI

  • Space-time techniques for computational aerodynamics modeling of flapping wings of an actual locust

    Takizawa K, Henicke B, Puntel A, Kostov N, Tezduyar T.E

    Computational Mechanics   50 ( 6 ) 743 - 760  2012年12月  [査読有り]

    DOI

  • Space-time computational analysis of bio-inspired flapping-wing aerodynamics of a micro aerial vehicle

    Takizawa K, Kostov N, Puntel A, Henicke B, Tezduyar T.E

    Computational Mechanics   50 ( 6 ) 761 - 778  2012年12月  [査読有り]

    DOI

  • Patient-specific computer modeling of blood flow in cerebral arteries with aneurysm and stent

    Takizawa K, Schjodt K, Puntel A, Kostov N, Tezduyar T.E

    Computational Mechanics   50 ( 6 ) 675 - 686  2012年12月  [査読有り]

    DOI

  • Fluid-structure interaction modeling of ringsail parachutes with disreefing and modified geometric porosity

    Takizawa K, Fritze M, Montes D, Spielman T, Tezduyar T. E

    Computational Mechanics   50 ( 6 ) 835 - 854  2012年12月  [査読有り]

    DOI

  • Computational fluid mechanics and fluid-structure interaction

    Takizawa K, Bazilevs Y, Tezduyar T.E

    Computational Mechanics   50 ( 6 ) 665 - 665  2012年12月  [査読有り]

    DOI

  • Space-time fluid-structure interaction methods

    Kenji Takizawa, Tayfun E. Tezduyar

    Mathematical Models and Methods in Applied Sciences   22 ( 2 )  2012年08月  [査読有り]

     概要を見る

    Since its introduction in 1991 for computation of flow problems with moving boundaries and interfaces, the Deforming-Spatial-Domain/Stabilized SpaceTime (DSD/SST) formulation has been applied to a diverse set of challenging problems. The classes of problems computed include free-surface and two-fluid flows, fluidobject, fluidparticle and fluidstructure interaction (FSI), and flows with mechanical components in fast, linear or rotational relative motion. The DSD/SST formulation, as a core technology, is being used for some of the most challenging FSI problems, including parachute modeling and arterial FSI. Versions of the DSD/SST formulation introduced in recent years serve as lower-cost alternatives. More recent variational multiscale (VMS) version, which is called DSD/SST-VMST (and also ST-VMS), has brought better computational accuracy and serves as a reliable turbulence model. Special spacetime FSI techniques introduced for specific classes of problems, such as parachute modeling and arterial FSI, have increased the scope and accuracy of the FSI modeling in those classes of computations. This paper provides an overview of the core spacetime FSI technique, its recent versions, and the special spacetime FSI techniques. The paper includes test computations with the DSD/SST-VMST technique. © 2012 World Scientific Publishing Company.

    DOI

  • ALE-VMS and ST-VMS methods for computer modeling of wind-turbine rotor aerodynamics and fluid-structure interaction

    Yuri Bazilevs, Ming-Chen Hsu, Kenji Takizawa, Tayfun E. Tezduyar

    Mathematical Models and Methods in Applied Sciences   22 ( 2 )  2012年08月  [査読有り]

     概要を見る

    We provide an overview of the Arbitrary LagrangianEulerian Variational Multiscale (ALE-VMS) and SpaceTime Variational Multiscale (ST-VMS) methods we have developed for computer modeling of wind-turbine rotor aerodynamics and fluidstructure interaction (FSI). The related techniques described include weak enforcement of the essential boundary conditions, KirchhoffLove shell modeling of the rotor-blade structure, NURBS-based isogeometric analysis, and full FSI coupling. We present results from application of these methods to computer modeling of NREL 5MW and NREL Phase VI wind-turbine rotors at full scale, including comparison with experimental data. © 2012 World Scientific Publishing Company.

    DOI

  • SPACE-TIME FLUID-STRUCTURE INTERACTION METHODS

    Takizawa K, Tezduyar T. E

    Mathematical Models & Methods in Applied Sciences   22 ( SUPPL.2 )  2012年08月  [査読有り]

    DOI

  • ALE-VMS AND ST-VMS METHODS FOR COMPUTER MODELING OF WIND-TURBINE ROTOR AERODYNAMICS AND FLUID-STRUCTURE INTERACTION

    Bazilevs Y, Hsu M. C, Takizawa K, Tezduyar T. E

    Mathematical Models & Methods in Applied Sciences   22 ( SUPPL.2 )  2012年08月  [査読有り]

    DOI

  • Space-Time and ALE-VMS Techniques for Patient-Specific Cardiovascular Fluid-Structure Interaction Modeling

    Takizawa Kenji, Bazilevs Yuri, Tezduyar Tayfun E

    Archives of Computational Methods in Engineering   19 ( 2 ) 171 - 225  2012年06月  [査読有り]

    DOI

  • Computational Methods for Parachute Fluid-Structure Interactions

    Takizawa Kenji, Tezduyar Tayfun E

    Archives of Computational Methods in Engineering   19 ( 1 ) 125 - 169  2012年03月  [査読有り]

    DOI

  • Special Issue on Computational Fluid Mechanics and Fluid-Structure Interaction Preface

    Bazilevs Y, Takizawa K, Tezduyar T. E

    Journal of Applied Mechanics-Transactions of the Asme   79 ( 1 )  2012年01月  [査読有り]

    DOI

  • Space-Time Computational Techniques for the Aerodynamics of Flapping Wings

    Takizawa Kenji, Henicke Bradley, Puntel Anthony, Spielman Timothy, Tezduyar Tayfun E

    Journal of Applied Mechanics-Transactions of the Asme   79 ( 1 )  2012年01月  [査読有り]

    DOI

  • Fluid-Structure Interaction Modeling of Spacecraft Parachutes for Simulation-Based Design

    Takizawa Kenji, Spielman Timothy, Moorman Creighton, Tezduyar Tayfun E

    Journal of Applied Mechanics-Transactions of the Asme   79 ( 1 )  2012年01月  [査読有り]

    DOI

  • Bringing tsheamf edloywn

    Takizawa K, Tezduyar T.E

    Mechanical Engineering   134 ( 12 ) 34 - 37  2012年  [査読有り]

  • A Comparative Study Based on Patient-Specific Fluid-Structure Interaction Modeling of Cerebral Aneurysms

    Takizawa Kenji, Brummer Tyler, Tezduyar Tayfun E, Chen Peng R

    Journal of Applied Mechanics-Transactions of the Asme   79 ( 1 )  2012年01月  [査読有り]

    DOI

  • Numerical-performance studies for the stabilized space-time computation of wind-turbine rotor aerodynamics

    Takizawa Kenji, Henicke Bradley, Montes Darren, Tezduyar Tayfun E, Hsu Ming-Chen, Bazilevs Yuri

    Computational Mechanics   48 ( 6 ) 647 - 657  2011年12月  [査読有り]

    DOI

  • Space-time fluid-structure interaction modeling of patient-specific cerebral aneurysms

    Tezduyar T. E, Takizawa K, Brummer T, Chen P. R

    International Journal for Numerical Methods in Biomedical Engineering   27 ( 11 ) 1665 - 1710  2011年11月  [査読有り]

    DOI

  • Stabilized space-time computation of wind-turbine rotor aerodynamics

    Takizawa K, Henicke B, Tezduyar T. E, Hsu M. C, Bazilevs Y

    Computational Mechanics   48 ( 3 ) 333 - 344  2011年09月  [査読有り]

    DOI

  • Special issue on computational fluid mechanics and fluid-structure interaction Preface

    Bazilevs Y, Takizawa K, Tezduyar T. E

    Computational Mechanics   48 ( 3 ) 245 - 245  2011年09月  [査読有り]

    DOI

  • Space-time FSI modeling and dynamical analysis of spacecraft parachutes and parachute clusters

    Takizawa K, Spielman T, Tezduyar T. E

    Computational Mechanics   48 ( 3 ) 345 - 364  2011年09月  [査読有り]

    DOI

  • Multiscale space-time fluid-structure interaction techniques

    Takizawa K, Tezduyar T. E

    Computational Mechanics   48 ( 3 ) 247 - 267  2011年09月  [査読有り]

    DOI

  • A parallel sparse algorithm targeting arterial fluid mechanics computations

    Manguoglu M, Takizawa K, Sameh A. H, Tezduyar T. E

    Computational Mechanics   48 ( 3 ) 377 - 384  2011年09月  [査読有り]

    DOI

  • Space-time fsi modeling of ringsail parachute clusters

    Takizawa K, Spielman T, Tezduyar T.E

    Structural Membranes 2011 - 5th International Conference on Textile Composites and Inflatable Structures     55 - 66  2011年  [査読有り]

  • Space-time FSI modeling and dynamical analysis of ringsail parachute clusters

    Takizawa K, Spielman T, Tezduyar T.E

    Proceedings of the 4th International Conference on Computational Methods for Coupled Problems in Science and Engineering, COUPLED PROBLEMS 2011     43 - 54  2011年  [査読有り]

  • Patient-specific arterial fluid-structure interaction modeling of cerebral aneurysms

    Takizawa K, Moorman C, Wright S, Purdue J, McPhail T, Chen P. R, Warren J, Tezduyar T. E

    International Journal for Numerical Methods in Fluids   65 ( 1-3 ) 308 - 323  2011年01月  [査読有り]

    DOI

  • Nested and parallel sparse algorithms for arterial fluid mechanics computations with boundary layer mesh refinement

    Manguoglu M, Takizawa K, Sameh A. H, Tezduyar T. E

    International Journal for Numerical Methods in Fluids   65 ( 1-3 ) 135 - 149  2011年01月  [査読有り]

    DOI

  • Multiscale space-time computation techniques

    Takizawa K, Tezduyar T.E

    Proceedings of the 4th International Conference on Computational Methods for Coupled Problems in Science and Engineering, COUPLED PROBLEMS 2011     611 - 622  2011年  [査読有り]

  • Multiscale sequentially-coupled FSI computation in parachute modeling

    Takizawa K, Wright S, Christopher J, Tezduyar T.E

    Structural Membranes 2011 - 5th International Conference on Textile Composites and Inflatable Structures     385 - 396  2011年  [査読有り]

  • Fluid-Structure Interaction Modeling of Ringsail Parachute Clusters

    K. Takizawa, T. Spielman, T. E. Tezduyar

    RECENT PROGRESSES IN FLUID DYNAMICS RESEARCH - PROCEEDINGS OF THE SIXTH INTERNATIONAL CONFERENCE ON FLUID MECHANICS   1376   7 - 11  2011年  [査読有り]

     概要を見る

    The team for advanced flow simulation and modeling (T star AFSM) has successfully addressed many of the computational challenges involved in fluid-structure interaction (FSI) modeling of ringsail parachutes, including the geometric complexities, and recently started addressing the challenges related to the contact between the parachutes of a cluster. This is being accomplished with the stabilized space-time FSI technique, which was developed by the T star AFSM and serves as the core numerical technology, and the special techniques developed by the T star AFSM. We present the results obtained with the FSI computation of parachute clusters and the related dynamical analysis.

    DOI

  • Fluid-structure interaction modeling of parachute clusters

    Takizawa K, Wright S, Moorman C, Tezduyar T.E

    International Journal for Numerical Methods in Fluids   65 ( 1-3 ) 286 - 307  2011年01月  [査読有り]

    DOI

  • Fluid-structure interaction modeling and performance analysis of the Orion spacecraft parachutes

    Takizawa K, Moorman C, Wright S, Spielman T, Tezduyar T.E

    International Journal for Numerical Methods in Fluids   65 ( 1-3 ) 271 - 285  2011年01月  [査読有り]

    DOI

  • Comparative patient-specific fsi modeling of cerebral aneurysms

    Takizawa K, Brummer T, Tezduyar T.E, Chen P.R

    Proceedings of the 4th International Conference on Computational Methods for Coupled Problems in Science and Engineering, COUPLED PROBLEMS 2011     590 - 599  2011年  [査読有り]

  • 3D simulation of wind turbine rotors at full scale. Part I: Geometry modeling and aerodynamics

    Y. Bazilevs, M. -C. Hsu, I. Akkerman, S. Wright, K. Takizawa, B. Henicke, T. Spielman, T. E. Tezduyar

    INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS   65 ( 1-3 ) 207 - 235  2011年01月  [査読有り]

     概要を見る

    In this two-part paper we present a collection of numerical methods combined into a single framework, which has the potential for a successful application to wind turbine rotor modeling and simulation. In Part 1 of this paper we focus on: 1. The basics of geometry modeling and analysis-suitable geometry construction for wind turbine rotors; 2. The fluid mechanics formulation and its suitability and accuracy for rotating turbulent flows; 3. The coupling of air flow and a rotating rigid body. In Part 2 we focus on the structural discretization for wind turbine blades and the details of the fluid-structure interaction computational procedures. The methods developed are applied to the simulation of the NREL 5MW offshore baseline wind turbine rotor. The simulations are performed at realistic wind velocity and rotor speed conditions and at full spatial scale. Validation against published data is presented and possibilities of the newly developed computational framework are illustrated on several examples. Copyright (C) 2010 John Wiley & Sons, Ltd.

    DOI

  • Space-time finite element computation of complex fluid-structure interactions

    Tezduyar T. E, Takizawa K, Moorman C, Wright S, Christopher J

    International Journal for Numerical Methods in Fluids   64 ( 10-12 ) 1201 - 1218  2010年12月  [査読有り]

    DOI

  • Wall shear stress calculations in space-time finite element computation of arterial fluid-structure interactions

    Takizawa K, Moorman C, Wright S, Christopher J, Tezduyar T.E

    Computational Mechanics   46 ( 1 ) 31 - 41  2010年06月  [査読有り]

    DOI

  • Solution of linear systems in arterial fluid mechanics computations with boundary layer mesh refinement

    Manguoglu M, Takizawa K, Sameh A. H, Tezduyar T. E

    Computational Mechanics   46 ( 1 ) 83 - 89  2010年06月  [査読有り]

    DOI

  • Multiscale sequentially-coupled arterial FSI technique

    Tezduyar T. E, Takizawa K, Moorman C, Wright S, Christopher J

    Computational Mechanics   46 ( 1 ) 17 - 29  2010年06月  [査読有り]

    DOI

  • Space-time finite element computation of arterial fluid-structure interactions with patient-specific data

    Takizawa K, Christopher J, Tezduyar T.E, Sathe S

    International Journal for Numerical Methods in Biomedical Engineering   26 ( 1 ) 101 - 116  2010年01月  [査読有り]

    DOI

  • Computer modeling and analysis of the Orion spacecraft parachutes

    Takizawa K, Moorman C, Wright S, Tezduyar T.E

    Lecture Notes in Computational Science and Engineering   73 LNCSE   53 - 81  2010年  [査読有り]

    DOI

  • Recent advances of multi-phase flow computation with the adaptive soroban-grid cubic interpolated propagation (CIP) method

    Takashi Yabe, Youichi Ogata, Kenji Takizawa

    Computational Fluid Dynamics 2006 - Proceedings of the Fourth International Conference on Computational Fluid Dynamics, ICCFD 2006     29 - 43  2009年  [査読有り]

    DOI

  • Conservative form of interpolated differential operator scheme for compressible and incompressible fluid dynamics

    Imai Y, Aoki T, Takizawa K

    Journal of Computational Physics   227 ( 4 ) 2263 - 2285  2008年02月  [査読有り]

    DOI

  • Ship hydrodynamics computations with the CIP method based on adaptive Soroban grids

    Takizawa Kenji, Tanizawa Katsuji, Yabe Takashi, Tezduyar Tayfun E

    International Journal for Numerical Methods in Fluids   54 ( 6-8 ) 1011 - 1019  2007年06月  [査読有り]

    DOI

  • Computation of free-surface flows and fluid-object interactions with the CIP method based on adaptive meshless soroban grids

    Takizawa K, Yabe T, Tsugawa Y, Tezduyar T.E, Mizoe H

    Computational Mechanics   40 ( 1 ) 167 - 183  2007年06月  [査読有り]

    DOI

  • Computation of fluid-solid and fluid-fluid interfaces with the CIP method based on adaptive Soroban grids - An overview

    Yabe Takashi, Takizawa Kenji, Tezduyar Tayfun E, Im Hyo-Nam

    International Journal for Numerical Methods in Fluids   54 ( 6-8 ) 841 - 853  2007年06月  [査読有り]

    DOI

  • 2203 保存形IDO法による圧縮性および非圧縮性流体解法(S01-1 CIP法の新展開と保存形(1),S01 CIP法の新展開と保存形)

    今井 陽介, 青木 尊之, 滝沢 研二

    年次大会講演論文集   2006   83 - 84  2006年

     概要を見る

    A conservative form of Interpolated Differential Operator (IDO) scheme (IDO-CF) is presented for compressible and incompressible fluid dynamics. Fluid equations are solved for multi-moments those are volume integral, surface integral, line integral, and point value of conservative quantities. For Riemann problems of compressible fluid flow, the IDO-CF scheme gives the same or better results compared with Riemann solvers. Direct Numerical Simulation of incompressible turbulent flow shows that the proposed scheme has better resolution than that of non-conservative form of the IDO scheme.

    DOI CiNii

  • The analysis of electromagnetic waves using CIP scheme with Soroban grid

    Ogata, Yoichi, Yabe, Takashi, Takizawa, Kenji, Ohkubo, Tomomasa

    COMPUTATIONAL FLUID DYNAMICS 2004, PROCEEDINGS     141 - +  2006年  [査読有り]

     概要を見る

    In the regime of finite-difference solutions for Maxwell's equations, all kinds of methods like FDTD (Finite-Difference Time-Domain) method, LBS (Linear Bicharacteristics Scheme) and so on, have been standard. However, in order to deal with large scale and complicated structure in future, higher order scheme and adaptive mesh that does not lose accuracy are required. In this paper, we propose the new method that uses the CIP (constrained interpolation profile/cubic interpolated propagation) method in combination with the numerical method of characteristics (hereafter, CIP-MOC) and the Soroban grid.

    DOI

  • Simulation and experiment on swimming fish and skimmer by CIP method

    K Takizawa, T Yabe, M Chino, T Kawai, K Wataji, H Hoshino, T Watanabe

    COMPUTERS & STRUCTURES   83 ( 6-7 ) 397 - 408  2005年02月  [査読有り]

     概要を見る

    The Cubic-Interpolated Propagation/Constrained Interpolation Profile (CIP) method is applied to the fluid-structure interaction like swimming fish and skimmer in the Cartesian grid system. These subjects require accurate calculation of pressure on the surface of the moving body. Using the accurate profile of pressure inside a grid cell, we estimate the force acting on the rigid body even if the rigid body has a structure in a scale smaller than grid cell. The CIP method is used to define such subgrid-scale structure. The experiments are performed to show the accuracy of the simulations. (C) 2005 Published by Elsevier Ltd.

    DOI

  • Challenge of CIP as a universal solver for solid, liquid and gas

    T Yabe, K Takizawa, A Chino, A Imai, CC Chu

    INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS   47 ( 6-7 ) 655 - 676  2005年02月  [査読有り]

     概要を見る

    We review some recent progress of the CIP method that is known as a general numerical solver for solid, liquid, gas and plasmas. This method is a kind of semi-Lagrangian scheme and has been extended to treat incompressible flow in the framework of compressible fluid. Since it uses primitive Euler representation, it is suitable for multi-phase analysis. Some applications to skimmer, swimming fish and laser cutting are presented. This method is recently extended to almost mesh-free system that is called 'soroban grid' that ensures the third-order accuracy both in time and space with the help of the CIP method. Copyright (C) 2005 John Wiley Sons, Ltd.

    DOI

  • Soroban格子法に基づく浅水2次元自由水面流れの計算手法の開発

    中村恭志, 石川忠晴, 矢部孝, 滝沢研二

    水工学論文集   49   685 - 690  2005年  [査読有り]

    DOI

  • A new paradigm of computer graphics by universal solver for solid, liquid and gas

    T Yabe, K Takizawa, F Xiao, T Aoki, T Himeno, T Takahashi, A Kunimatsu

    JSME INTERNATIONAL JOURNAL SERIES B-FLUIDS AND THERMAL ENGINEERING   47 ( 4 ) 656 - 663  2004年11月  [査読有り]

     概要を見る

    We propose a new algorithm for producing computer graphics of melting and evaporation process of matter. Such a computation becomes possible by a universal solver for solid, liquid and gas based on the CIP (Cubic-Interpolated Propagation / Constrained Interpolation Profile) method proposed by one of the authors. This method can also be applied to the movement, deformation and even break up of solid, liquid and gas in one simple algorithm. Therefore seamless computation of all the phases of matter becomes possible. This enables us to reproduce natural phenomena in some instances by computation. In order to demonstrate this reality, we show how precisely the computational result replicates the movies of real phenomena. The flattering motions of metal disk in water and thin name card in air are treated showing accuracy of force calculation on the surface of sub-grid scale. Although the CIP uses semi-Lagrangian form algorithm, the exact mass conservation is guaranteed by additional tool. By using this scheme, separation of a bubble in bifurcation tube and splashing of water surface are successfully simulated.

    DOI

  • Higher-order schemes with CIP method and adaptive Soroban grid towards mesh-free scheme

    T Yabe, H Mizoe, K Takizawa, H Moriki, HN Im, Y Ogata

    JOURNAL OF COMPUTATIONAL PHYSICS   194 ( 1 ) 57 - 77  2004年02月  [査読有り]

     概要を見る

    A new class of body-fitted grid system that can keep the third-order accuracy in time and space is proposed with the help of the CIP (constrained interpolation profile/cubic interpolated propagation) method. The grid system consists of the straight lines and grid points moving along these lines like abacus - Soroban in Japanese. The length of each line and the number of grid points in each line can be different. The CIP scheme is suitable to this mesh system and the calculation of large CFL (&gt;10) at locally refined mesh is easily performed. Mesh generation and searching of upstream departure point are very simple and almost mesh-free treatment is possible. Adaptive grid movement and local mesh refinement are demonstrated. (C) 2003 Elsevier B.V. All rights reserved.

    DOI

  • 219 曲線座標系での高次精度解法

    矢部 孝, 滝沢 研二

    年次大会講演論文集   2003   27 - 28  2003年

     概要を見る

    We propose a scheme that has the third-order accuracy both in time and space, and can be used in curvilinear system. The method is based on the CIP method and Soroban grid. Although the mesh is used tentatively, it does not need the connectivity of the grid and is a class of mesh-less scheme. Some benchmark test programs are proposed to check the accuracy in curvilinear coordinate.

    DOI CiNii

  • Three-dimensional simulation of skimmer on water

    Takizawa K, Yabe T

    Proceedings of the ASME/JSME Joint Fluids Engineering Conference   1 A   509 - 514  2003年  [査読有り]

  • Experimental research on rotating skimmer

    Chino M, Takizawa K, Yabe T

    Proceedings of the ASME/JSME Joint Fluids Engineering Conference   1 A   515 - 518  2003年  [査読有り]

  • The next generation CIP as a conservative semi-Lagrangian solver for solid, liquid and gas

    T Yabe, Y Ogata, K Takizawa, T Kawai, A Segawa, K Sakurai

    JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS   149 ( 1 ) 267 - 277  2002年12月  [査読有り]

     概要を見る

    We present a review of the CIP method, which is a kind of semi-Lagrangian scheme and has been extended to treat incompressible flow in the framework of compressible fluid. Since it uses primitive Euler representation, it is suitable for multi-phase analysis. The recent version of this method guarantees the exact mass conservation even in the framework of semi-Lagrangian scheme. Comprehensive review is given for the strategy of the CIP method that has a compact support and subcell resolution including front capturing algorithm with functional transformation. (C) 2002 Elsevier Science B.V. All rights reserved.

    DOI

  • The next generation CIP as a conservative semi-Lagrangian solver for solid, liquid and gas

    T Yabe, Y Ogata, K Takizawa, T Kawai, A Segawa, K Sakurai

    JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS   149 ( 1 ) 267 - 277  2002年12月  [査読有り]

     概要を見る

    We present a review of the CIP method, which is a kind of semi-Lagrangian scheme and has been extended to treat incompressible flow in the framework of compressible fluid. Since it uses primitive Euler representation, it is suitable for multi-phase analysis. The recent version of this method guarantees the exact mass conservation even in the framework of semi-Lagrangian scheme. Comprehensive review is given for the strategy of the CIP method that has a compact support and subcell resolution including front capturing algorithm with functional transformation. (C) 2002 Elsevier Science B.V. All rights reserved.

    DOI DOI2

  • Multi-dimensional semi-Lagrangian scheme that guarantees exact conservation

    K Takizawa, T Yabe, T Nakamura

    COMPUTER PHYSICS COMMUNICATIONS   148 ( 2 ) 137 - 159  2002年10月  [査読有り]

     概要を見る

    A new numerical method that guarantees exact mass conservation is proposed to solve multi-dimensional hyperbolic equations in semi-Lagrangian form without directional splitting. The method is based on a concept of CIP scheme and keep the many good characteristics of the original CIP scheme. The CIP strategy is applied to the integral form of variable. Although the advection and non-advection terms are separately treated, the mass conservation is kept in a form of spatial profile inside a grid cell. Therefore, it retains various advantages of the semi-Lagrangian schemes with exact conservation that has been beyond the capability of conventional semi-Lagrangian schemes. (C) 2002 Elsevier Science B.V. All rights reserved.

    DOI

  • Multi-dimensional semi-Lagrangian scheme that guarantees exact conservation

    K Takizawa, T Yabe, T Nakamura

    COMPUTER PHYSICS COMMUNICATIONS   148 ( 2 ) 137 - 159  2002年10月  [査読有り]

     概要を見る

    A new numerical method that guarantees exact mass conservation is proposed to solve multi-dimensional hyperbolic equations in semi-Lagrangian form without directional splitting. The method is based on a concept of CIP scheme and keep the many good characteristics of the original CIP scheme. The CIP strategy is applied to the integral form of variable. Although the advection and non-advection terms are separately treated, the mass conservation is kept in a form of spatial profile inside a grid cell. Therefore, it retains various advantages of the semi-Lagrangian schemes with exact conservation that has been beyond the capability of conventional semi-Lagrangian schemes. (C) 2002 Elsevier Science B.V. All rights reserved.

    DOI DOI2

  • Three-phase flow calculation with conservative semi-Lagrangian CIP method

    T. Yabe, F. Xiao, K. Takizawa, K. Sakurai

    American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FED   257 ( 2 A ) 467 - 472  2002年  [査読有り]

     概要を見る

    We present a review of the CIP method, which is a kind of semi-Lagrangian scheme and has been extended to treat incompressible flow in the framework of compressible fluid. Since it uses primitive Euler representation, it is suitable for multi-phase analysis. The recent version of this method guarantees the exact mass conservation even in the framework of semi-Lagrangian scheme. Comprehensive review is given for the strategy of the CIP method that has a compact support and sub-cell resolution including front capturing algorithm with functional transformation.

    DOI

  • Exactly conservative semi-Lagrangian scheme for multi-dimensional hyperbolic equations with directional splitting technique (vol 174, pg 171, 2001)

    T Nakamura, R Tanaka, T Yabe, K Takizawa

    JOURNAL OF COMPUTATIONAL PHYSICS   175 ( 2 ) 792 - 792  2002年01月  [査読有り]

    DOI

▼全件表示

書籍等出版物

  • Computational fluid-structure interaction: Methods and applications

    Y. Bazilevs, K. Takizawa, T.E. Tezduyar

    John Wiley  2013年02月 ISBN: 9780470978771

  • CIP法とJavaによるCGシミュレーション

    矢部 孝, 尾形 陽一, 滝沢 研二

    森北出版  2007年02月 ISBN: 9784627919112

Misc

  • 招待講演 医用画像を用いた血流シミュレーションと幾何学的特徴量抽出 (医用画像)

    水藤 寛, Huynh Q. H. Viet, 滝沢 研二, 植田 琢也

    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報   117 ( 117 ) 31 - 33  2017年07月

    CiNii

  • Estimation of Leakage Flow Between an Engine Cylinder and Moving Piston with the Space-Time Isogeometric Analysis

    大森 正也, 倉石 孝, 滝沢 研二, Tezduyar Tayfun E.

    計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science   22   4p  2017年05月

    CiNii

  • Fluid and Structure Analysis of Human Aorta : Fluid Mechanics Analysis with Space-Time Isogeometric Discretization

    内河 寛明, 寺原 拓哉, 佐々木 崇史, 滝沢 研二, Tezduyar Tayfun E.

    計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science   22   4p  2017年05月

    CiNii

  • Fluid and Structure Analysis of the Human Aorta : Zero-Stress State Estimation with T-Spline Discretization

    吉田 彩花, 佐々木 崇史, 寺原 拓哉, 滝沢 研二, Tezduyar Tayfun E.

    計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science   22   3p  2017年05月

    CiNii

  • Space-Time Isogeometric Analysis of Aortic-Valve Fluid Mechanics and Flow Validation Near the Leaflet Surfaces

    塩崎 健介, 寺原 拓哉, 佐々木 崇史, 滝沢 研二, Tezduyar Tayfun E.

    計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science   22   4p  2017年05月

    CiNii

  • 滑らかな形状および境界層の高解像による血管内脈動流の周期性に関する研究

    内河 寛明, 佐々木 崇史, 寺原 拓哉, 滝沢 研二, テズドゥヤー タイフン

    計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science   21   4p  2016年05月

    CiNii

  • 大動脈弁の非対称開閉時の弁近傍流れの詳細解析

    寺原 拓哉, 滝沢 研二, Tezduyar E. Tayfun, 佐々木 崇史

    計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science   21   3p  2016年05月

    CiNii

  • 数値解析による脈動流を伴うターボチャージャータービンの性能評価

    乙黒 雄斗, 滝沢 研二, Tezduyar E. Tayfun, 望月 寛己

    計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science   21   4p  2016年05月

    CiNii

  • Tire Flow Analysis with Actual Tire Geometry, Tire Deformation and Road Contact

    倉石 孝, 滝沢 研二, 浅田 奨平, テズドゥヤー タイフン

    計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science   21   6p  2016年05月

    CiNii

  • Disk-Gap-Bandパラシュートの高精度な形状および境界層表現による超音速流れ解析

    金井 太郎, 滝沢 研二, Tezduyar Tayfun E.

    年会講演会講演集   47   3p  2016年04月

    CiNii

  • 1E33 NURBSを用いた大動脈ゼロストレス状態の推定

    佐々木 崇史, 滝沢 研二, 内河 寛明, TEZDUYAR Tayfun E., 板谷 慶一

    バイオエンジニアリング講演会講演論文集   2016 ( 28 ) "1E33 - 1"-"1E33-3"  2016年01月

     概要を見る

    This research objective is to develop a time-dependent arterial wall modeling for arterial fluid-structure interaction. The computation has two challenges: (1) In the conventional method of representing the arterial lumen from medical images, there is no material-point correspondence between the representations for different instants during the cardiac cycle. (2) A zero-stress state (ZSS) needs to be estimated. The ZSS is related to the residual stress, which is normally acquired from cutting/opening the model, but here the only arterial-data source is medical images. Arterial lumens from medical images are shapes coming by deformation from the ZSS. Therefore, we propose a mapping method for that deformation that takes into account the physical properties of the artery, establishing the material-point correspondence needed. On the other hand, our current ZSS estimation method is only for finite element representation. Here, we extend the method to non-uniform rational B-spline (NURBS) representation to have higher continuities and convergence rates. Combining these two methods, material-point correspondence between the representations for different instants has been established.

    CiNii

  • Disk-Gap-Bandパラシュートの空気力学特性解析

    金井 太郎, 滝沢 研二, Tezduyar Tayfun E.

    計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science   20   3p  2015年06月

    CiNii

  • 2A15 胸部大動脈の形状と壁面応力分布及び病態の関係(OS11-3:生体流れの計算バイオメカニクス:疾病の再現および診断・治療への応用(3))

    水藤 寛, 滝沢 研二, TEZDUYAR Tayfun E., 植田 琢也

    バイオエンジニアリング講演会講演論文集   2015 ( 27 ) 309 - 309  2015年01月

    CiNii

  • 2A23 Element-Based Zero-Stress State推定法による動脈壁モデル構築および医療画像の写像(OS11-4:生体流れの計算バイオメカニクス:疾病の再現および診断・治療への応用(4))

    佐々木 崇史, 滝沢 研二, 板谷 慶一, 高木 裕和, Tezduyar Tayfun E., 宮崎 翔平, 宮地 鑑

    バイオエンジニアリング講演会講演論文集   2015 ( 27 ) 315 - 316  2015年01月

    CiNii

  • Geometric Porosityを解像したリングセールパラシュートの数値流体解析

    筒井 雄樹, 藤 成美, 寺原 拓哉, 滝沢 研二, Tezduyar Tayfun E., Boswell Cody

    計算力学講演会講演論文集   2014 ( 27 ) 399 - 400  2014年11月

    CiNii

  • A114 Element-Based Zero-Stress State推定法を用いた大動脈計算(A1-3 数理・計算バイオメカニクス3,分散体バイオメカニクス)

    佐々木 崇史, 滝沢 研二, 板谷 慶一, 高木 裕和, Tezduyar Tayfun E., 宮崎 翔平, 宮地 鑑

    バイオフロンティア講演会講演論文集   2014 ( 25 ) 25 - 26  2014年10月

    CiNii

  • シミュレーションを通した臨床医療と数理科学の協働(シミュレーションの世界)

    水藤 寛, 滝沢 研二, 植田 琢也

    シミュレーション   33 ( 3 ) 231 - 233  2014年09月

    CiNii

  • 1G26 Aortic-Valve Simulation with a High-Accuracy Method

    滝沢 研二, 浅田 奨平, BUSCHER Austin, TEZDUYAR Tayfun

    バイオエンジニアリング講演会講演論文集   2014 ( 26 ) 229 - 230  2014年01月

    CiNii

  • 1G31 Three-Layer Wall Modeling for Aortic Dissection

    高木 裕和, 滝沢 研二, 杉原 健太, TEZDUYAR Tayfun

    バイオエンジニアリング講演会講演論文集   2014 ( 26 ) 231 - 232  2014年01月

    CiNii

  • 1G25 大動脈瘤の発生・増大機序理解のための血流解析(OS5-2:生体流れの計算バイオメカニクス:疾病の再現および診断・治療への応用(2))

    水藤 寛, HUYNH Viet H. Q., 滝沢 研二, TEZDUYAR Tayfun E., 植田 琢也

    バイオエンジニアリング講演会講演論文集   2014 ( 26 ) 227 - 227  2014年01月

    CiNii

  • 2607 動脈血流解析における動脈初期ストレス推定法

    高木 裕和, 滝沢 研二, Tezduyar Tayfun E, 鳥井 亮

    計算力学講演会講演論文集   2013 ( 26 ) "2607 - 1"-"2607-3"  2013年11月

     概要を見る

    In patient-specific arterial fluid-structure interaction (FSI) computations, the image-based artenal geometry comes from a configuration that is not stress-free We present a method for estimation of element-based zero-stress (ZS) state The method has three main components, and we present one of them. An element-based mappmg between the artenal and straight-tube configuration is used for mappmg from the artenal configuration to the straight-tube configuration, and for mapping the estimated ZS state of the straight tube back to the artenal configuration, to be used as the initial guess for the iterative method that matches the image-based target shape We present a set of test computations to show how the method works

    CiNii

  • 2521 ディスクブレーキ周りの熱流体連成解析

    高木 裕和, 滝沢 研二, 田畑 伸一郎, Tezduyar Tayfun E

    計算力学講演会講演論文集   2013 ( 26 ) "2521 - 1"-"2521-2"  2013年11月

     概要を見る

    In the automotive industry, numerical analysis is often used as the design support and makes a great contribution In terms of brake disks, however, it is still difficult to predict heat fatigue of brake disks by numerical approach It is because cracks and textures of brake rotors result from interaction between temperature field, stress field and fluid field and their unsteadiness. In this discourse, we develop necessary methods to compute braking effects as mput heat flux for further thermo-fluid coupled computation

    CiNii

  • 2522 熱流体解析によるタイヤの熱伝達率予想

    田畑 伸一郎, 倉石 孝, 滝沢 研二, 高木 裕和, Rostov Nikolay, Tayfun E Tezduyar

    計算力学講演会講演論文集   2013 ( 26 ) "2522 - 1"-"2522-2"  2013年11月

    CiNii

  • 308 Space-Time法による人工弁の計算

    浅田 奨平, 滝沢 研二, BUSCHER Austin, TEZDUYAR Tayfun E.

    計算力学講演会講演論文集   2013 ( 26 ) "308 - 1"-"308-2"  2013年11月

    CiNii

  • Space-Time法による流体構造連成解析

    滝沢 研二, Tezduyar Tayfun E.

    フルードパワーシステム : 日本フルードパワーシステム学会誌 : journal of the Japan Fluid Power System Society   44 ( 5 ) 270 - 274  2013年09月

    CiNii

  • 2B16 Boundary fitted meshing for arterial flow analysis : Boundary fitted meshing for arterial flow analysis

    滝沢 研二, 高木 裕和, Kostov Nikolay, Tezduyar Tayfun E.

    バイオエンジニアリング講演会講演論文集   2013 ( 25 ) 302 - 302  2013年01月

    CiNii

  • 810 宇宙船のカバー除去パラシュートの流体構造連成(OS8-2.工学・医療工学における移動境界問題(2),OS・一般セッション講演)

    滝沢 研二, Montes Darren, Fritze Matthew, McIntyre Spenser, Boben Joseph, 筒井 雄樹, Tezduyar Tayfun E.

    計算力学講演会講演論文集   2012 ( 25 ) 19 - 20  2012年10月

     概要を見る

    宇宙船の帰還には,大型パラシュートを複数使用する必要がある.このような,大型パラシュートを宇宙船から開くためには,小さな穴からパラシュートを取り出すのは困難である.そこで,上部のカバーを取り除くことで容易に取り出す方法を採用する.この時,この上部のカバーを取り除く際,宇宙船自身の作る後部の流れにより,いったん離れたカバーが再び宇宙船に衝突してしまう危険がる.本研究は,安全にこのカバーを除去するため,パラシュートの使用を検討したものである.

    CiNii

  • 805 腹部大動脈瘤の増大機序理解のための流体構造連成シミュレーション(OS8-1.工学・医療工学における移動境界問題(1),OS・一般セッション講演)

    水藤 寛, 佐久間 理吏, 植田 琢也, 鈴木 宗村, 滝沢 研二, 琴岡 憲彦, 野出 孝一, Tezduyar Tyfun E.

    計算力学講演会講演論文集   2012 ( 25 ) 7 - 8  2012年10月

     概要を見る

    腹部大動脈瘤の増大の機序を理解する目的で、胸部から腹部の大動脈全体を対象として、流体構造連成を考慮した数値シミュレーションを行っている。大動脈の形状には個大差が大きく、それに由来する流れの様相の違いが、大動脈瘤の増大や、ステントグラフト治療の予後などに影響していると考えられるためである。流体構造連成解析の手法としては、Defbmming-Spatial-Domain/Stabilized-Space-Time(DSD/SST)法と変分マルチスケール法(VMS)に基づく流体構造連成解析手法(ST-VMS)(5-6)を用い、様々な症例の血管形状を用いて流れの場とそれによる壁面応力の違いを調べている。

    CiNii

  • 804 血流解析における長手方向の残留応力影響(OS8-1.工学・医療工学における移動境界問題(1),OS・一般セッション講演)

    滝沢 研二, 高木 裕和, Tezduyar Tayfun E.

    計算力学講演会講演論文集   2012 ( 25 ) 5 - 6  2012年10月

     概要を見る

    血流解析において,流体構造連成は極めて重要である.本研究では血管の変形を正しく計算するため残留応力の影響について検討する.血管をFungモデルで近似するが,同じモデルを用いたとしても残留応力によって著しく異なる.またFungモデルは線形でないため,逆解析によりゼロ圧力形状を推定することは原理的に難しく,血管の成長という観点から見ても妥当ではない.そこで,本研究では,円柱形状の血管モデルを用い,血管に対する知見をもとに,もっともらしい残留応力を推定するための計算を行う.

    CiNii

  • J025012 脳動脈瘤のステント処置効果予測のための数値解析

    滝沢 研二, Schjodt Kathleen, Kostov Nikolay, Puntel Anthony, 高木 裕和, Tezduyar Tayfun

    年次大会 : Mechanical Engineering Congress, Japan   2012   "J025012 - 1"-"J025012-3"  2012年09月

     概要を見る

    modeling of blood flow in cerebral arteries with aneurysm and stent. These techniques are used in conjunction with the core computational technique, which is the space-time version of the variational multiscale (VMS) method and is called "DST/SST-VMST." The special techniques include using NURBS for the spatial representation of the surface over which the stent mesh is built, mesh generation techniques for both the finite- and zero-thickness representations of the stent, techniques for generating refined layers of mesh near the arterial and stent surfaces, and models for representing double stent. First we compare the flow patterns obtained with the finite- and zero-thickness representations of the stent. We compute the unsteady flow patterns in the aneurysm and investigate how those patterns are influenced by the presence of single and double stents.

    CiNii

  • Computational Modeling of Parachute Fluid-Structure Interaction

    Takizawa Kenji, Fritze Matthew, Montes Darren

    計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science   17   4p  2012年05月

    CiNii

  • ソロバン格子CIP法による流体構造連成解析

    矢部孝, 尾形陽一, 滝沢研二

    混相流   23 ( 2 )  2009年

    J-GLOBAL

  • 高精度非構造ソロバン格子CIP法

    矢部孝, 滝沢研二, 尾形陽一

    応用数理   18 ( 2 ) 78 - 94  2008年

  • Ship Hydrodynamics Computations with the CIP Method Based on Adaptive Soroban Grids(Summaries of Papers Published by Staff of National Maritime Research Institute at Outside Organizations) :

    Takizawa Kenji, Tanizawa Katsuji, Yabe Takashi, Tezduyar Tayfun E.

    海上技術安全研究所報告   7 ( 3 ) 382 - 382  2007年

    CiNii

  • Computational Ship Hydrodynamics with the CIP Method(Summaries of Papers Published by Staff of National Maritime Research Institute at Outside Organizations) :

    滝沢 研二, 谷澤 克治, 矢部 孝, Tezduyar Tayfun E.

    海上技術安全研究所報告   7 ( 3 ) 384 - 384  2007年

    CiNii

  • 2006A-OS4-4 高次精度CFDによる水波と浮体の相互作用の計算(オーガナイズドセッション(OS4):水波と浮体の強非線形相互作用)

    滝沢 研二, 谷澤 克治

    日本船舶海洋工学会講演会論文集   ( 3 ) 73 - 74  2006年11月

    CiNii

  • ソロバン格子CIP法を用いた高次精度多層流計算法(所外発表論究等概要)

    矢部 孝, 滝沢 研二, Tezduyar T. E.

    海上技術安全研究所報告   6 ( 1 ) 73 - 73  2006年

    CiNii

  • 2605 ソロバン格子を用いたCIP法によるVLASOV方程式の解法(OS-26A CIP 法および多相流解析技術の最近の進展,OS-26 CIP 法および多相流解析技術の最近の進展)

    小田垣 光一, 矢部 孝, 滝沢 研二

    計算力学講演会講演論文集   2005 ( 18 ) 623 - 624  2005年11月

    CiNii

  • 2604 ソロバン格子CIP法による気液界面の捕獲(OS-26A CIP 法および多相流解析技術の最近の進展,OS-26 CIP 法および多相流解析技術の最近の進展)

    今井 正和, 櫻井 康隆, 矢部 孝, 滝沢 研二

    計算力学講演会講演論文集   2005 ( 18 ) 621 - 622  2005年11月

     概要を見る

    The soroban grid system that can capture the gas-liquid interface sharply is proposed. This grid system consists of the straight lines and grid points on these lines. Combination the flexible soroban mesh and the CIP (cubic interpolated propagation) method produces interface capturing and high order accuracy. Algorithm of mesh generation is very simple and the soroban mesh can be generated at short times.

    CiNii

  • ソロバン格子を用いた流体計算(OS2c CIP法とその周辺)

    滝沢 研二, 矢部 孝, Tezduyar Tayfun E.

    計算力学講演会講演論文集   2004 ( 17 ) 843 - 844  2004年11月

    CiNii

  • 連続的な水切り現象のシミュレーション(OS2a CIP法とその周辺)

    千野 実, 今井 正和, 滝沢 研二, 矢部 孝

    計算力学講演会講演論文集   2004 ( 17 ) 685 - 686  2004年11月

    CiNii

  • 1030 ソロバン格子によるメッシュフリー CIP 法

    矢部 孝, 尾形 陽一, 滝沢 研二, 津川 祐美子, 林 孝男

    計算力学講演会講演論文集   2003 ( 16 ) 971 - 972  2003年11月

    CiNii

  • 323 フリーメッシュスキームに向けた CIP 法とそろばん格子を用いた高次精度スキーム

    津川 祐美子, 矢部 孝, 滝沢 研二, 林 孝男

    計算力学講演会講演論文集   2003 ( 16 ) 215 - 216  2003年11月

    CiNii

  • CIP特性曲線法による電磁波伝播解析

    尾形陽一, 矢部孝, 太田弘毅, 滝沢研二, 大久保友雅, IM H

    日本機械学会計算力学講演会講演論文集   16th  2003年

    J-GLOBAL

  • 456 保存型 CIP 法による多相流解析

    滝沢 研二, 矢部 孝

    計算力学講演会講演論文集   2002 ( 15 ) 453 - 454  2002年10月

    CiNii

  • Universal solver CIP for all phases of matter

    T.Yabe, K.Takizawa, F.Xiao A.Ikebata

    Conference on Scientific Computing and Partial Differential Equations,On,the Occasion of Stanley Osher's 60th birthday. December 12-15, 2002 Lam Woo Conference Center, Hong Kong Baptist University, Hong Kong.    2002年

  • Exactly conservative semi-Lagrangian scheme for multi-dimensional hyperbolic equations with directional splitting technique

    T Nakamura, R Tanaka, T Yabe, K Takizawa

    JOURNAL OF COMPUTATIONAL PHYSICS   174 ( 1 ) 171 - 207  2001年11月

     概要を見る

    A new numerical method that guarantees exact mass conservation is proposed to solve multidimensional hyperbolic equations in semi-Lagrangian form. The method is based on the constrained interpolation profile (CIP) scheme and keeps the many good characteristics of the original CIP scheme. The CIP strategy is applied to the integral form of variables. Although the advection and nonadvection terms are separately treated, mass conservation is kept in the form of a spatial profile inside a grid cell. Therefore, it retains various advantages of the semi-Lagrangian solution with exact conservation, which has been beyond the capability of conventional semi-Lagrangian schemes. (C) 2001 Elsevier Science.

    DOI CiNii

▼全件表示

受賞

  • 日本学術振興会賞

    2018年12月   日本学術振興会  

    受賞者: 滝沢 研二

  • ナイスステップな研究者2017

    2016年12月   科学技術・学術政策研究所  

  • Highly Cited Researcher (Engineering)

    2016年11月   Thomson Reuters  

  • リサーチフロントアワード

    2016年07月   トムソン・ロイター  

  • 文部科学大臣表彰(若手科学者賞)

    2015年04月  

  • Thomas J.R. Hughes Young Investigator Award

    2012年11月  

  • Web of Science Highly Cited Researcher (Cross-Field)

    2018年11月   Clarivate Analytics  

    受賞者: 滝沢 研二

  • Highly Cited Researcher (Engineering)

    2017年11月   Clarivate Analytics  

  • Computational Mechanics Award

    2017年06月   日本計算力学連合  

  • Waseda Research Award (High-Impact Publication)

    2014年12月  

  • 日本機械学会計算力学部門業績賞

    2014年11月  

  • 2013 APACM Young Investigator Award

    2013年12月  

  • Fellow Award, Japan Association for Computational Mechanics

    2012年07月  

  • Young Investigator Award, International Association for Computational Mechanics

    2012年07月  

  • Best Computer Visualization Award, Third Asian-Pacific Congress on Computational Mechanics and Eleventh International Conference on Enhancement and Promotion of Computational Methods in Engineering and Science

    2007年12月  

  • 日本計算力学奨励賞

    2007年12月  

  • 第12回 計算工学講演会・ベストペーパーアワード

    2007年05月  

▼全件表示

共同研究・競争的資金等の研究課題

  • 赤血球の運動に着目した開閉する心臓弁の流体構造連成解析手法の構築

    日本学術振興会  科学研究費助成事業 基盤研究(A)

    研究期間:

    2018年04月
    -
    2023年03月
     

    滝沢 研二, 今井 陽介

     概要を見る

    心臓弁の開閉に伴い、その内側を流れる赤血球を含む血液は 1) 流速 3 m/s から急激に静止する強い非定常性、2) 弁尖同士に挟まれるという特異性がある。そのため、実験による観測が極めて困難である。さらに、これまでの数値計算ではこのようなものは再現出来ていない。そこで、この弁の開閉や赤血球の挙動およびそれらの相互作用を再現する手法を構築し、この現象を詳しく知ることを目的としている。
    <BR>
    本年度は弁近傍と赤血球に関する2点を中心に研究を進めた。まず、心臓弁に関しては弁の厚みの影響が重要であることを突き止めた。そもそも、非定常性の強い弁近傍の状態において弁の厚みは物理的に無視し難いということ、また実際に、厚みゼロとして計算していた従来の方法は、360度曲がっている状態となるため、その点における壁面せん断応力の表現方法が悪いことが分かった。そこで、厚みを表現するとともに滑らかな弁尖の再現している。これによって、弁尖の裏表の間に生じる壁面せん断応力を適正に表現できている。なお、これらのテスト計算においては、全体像を掴むためにまずは埋め込み境界法を用いた流体構造連成解析を用いた。これにより、流体構造連成問題のような複雑な動きのときにも、計算格子を動かすことが実現できることを確認した。
    赤血球に関しては当初より境界要素法を用いるタイプ・埋め込み境界法・物体適合格子を使うタイプを検討し、それぞれの欠点・利点を検討した。中でも制限の多い境界要素法について、活用するアイディアを検討するとともに文献の調査も行った。また赤血球の膜を表現する新たなモデルを考案した。

  • ものづくりHPCアプリケーションのエクサスケールへの進化

    日本学術振興会  科学研究費助成事業 基盤研究(S)

    研究期間:

    2014年05月
    -
    2019年03月
     

    青木 尊之, 森口 周二, 下川辺 隆史, 高木 知弘, 滝沢 研二

     概要を見る

    ① AMR法を適用した複雑形状物体を含んだ非圧縮性単相流体(乱流LES)シミュレーション:格子ボルツマン法による自転車競技を想定した流れの大規模なLES空力解析を行った。8人の集団走行における縦列配置とひし形配置の隊列位置における各自転車の空力抵抗を評価し、協議戦略に役立つ知見が得られた。また、72人の集団に対して22.3億格子を用いTSUBAME3.0の192個のGPUで計算し、中央部は先頭の5%の空力抵抗しか受けないことが明らかになった。
    ②マルチ・フェーズフィールド(MPF)法による動的領域分割:MPF法による粒成長をAMR格子を用いる並列計算の領域分割に適用した。分割領域が凸形状になるため、空間充填曲線を用いる方法より領域間通信を最大で30%低減することが明らかになった。
    ③AMR法による気液二相流シミュレーション:弱圧縮性流体計算に等温過程を導入することにより、これまでの特性線に基づいた手法よりも計算効率を向上させることができた。スッタッガード格子点配置になるが、Octreeベース細分化によるAMRをGPU実装することができた。
    ④流体-構造連成問題:瓦礫や木材などが自由界面を浮遊する流れに対し、流体計算にはCumulant型格子ボルツマン法を導入し、DEMで記述する浮遊物体との流体-構造連成問題の大規模計算を実行した。神戸大学の60m水槽実験との良好な一致を得た。
    ⑤Phase Field法による凝固と粒成長のシミュレーション:2元合金一方向凝固過程における多結晶競合成長のメカニズムを解明した。大規模Phase Field計算によって得られた柱状デンドライト構造に対し、格子ボルツマン法で液相流動を与えることでデンドライト樹間液相の透過率を高精度に予測した。また、MPF法の大規模計算結果を用いることで3次元粒成長挙動とその2次元断面の挙動の相関関係を示した。

  • 周期的定常流れに対する4次元流れ領域区分の定式化および数値解析法の提案

    日本学術振興会  科学研究費助成事業 挑戦的萌芽研究

    研究期間:

    2016年04月
    -
    2018年03月
     

    滝沢 研二, 野津 裕史

     概要を見る

    本研究では流れの状況を理解するために粒子滞在時間を用いる.これをオイラー形式に直すことで,領域全てにおいての時間変化が分かる.研究には脈動流下において周期流れを持つ大動脈流れと,回転部位を含む流体機械流れを用いる.滞在時間の周期変化は流体場を用いて計算し続けることで得られる.出口境界における滞在時間は理論によって推定することができ,計算がこの数字よりも低いとは,入口から出口と繋がっていない領域があることを意味する.そしてその領域では滞在時間を計算した時間と同等になることから時間変動する区分の指標となる事がわかる.本研究では,この計算の精度についても検討し工夫を行った.

  • ものづくり流体アプリケーションのエクサスケールへの進化

    日本学術振興会  科学研究費助成事業 基盤研究(A)

    研究期間:

    2014年04月
    -
    2015年03月
     

    青木 尊之, 高木 知弘, 滝沢 研二, 森口 周二, 下川辺 隆史

     概要を見る

    エクサスケールのスパコンにおいて、ものづくりを革新的に発展させるアプリケーションを開発するためには、既存のアプリケーションから根底から作り直す必要がある。所望する計算結果を得るまでの時間「Time to Solution」を最重要視した新しい陽的時間積分に基づいた数値計算手法と計算アルゴリズムを導入する研究を進めた。
    数値計算手法(離散化)に関して陰解法から陽解法、低次精度から高次精度空間離散化、非構造格子から局所的に均一な構造格子等への転換を行い、一方で計算アルゴリズムに対して、① データ移動の最小化、② 演算密度の向上、③ ノード間通信を隣接通信に限定等を行う。さらに詳細なパフォーマンス・モデルを構築し、エクサスケールの問題規模において高い実行性能を確実に達成する。手本となる流体アプリケーションの成功例を示し、ものづくり分野への大きな貢献を目的として研究に着手した。
    計算アルゴリズムの検討において、完全陽解法にすることで、ペタスケールの格子系アプリケーションで導入してきた演算と通信のオーバーラップによる通信時間の隠ぺいが計算の殆どの部分で可能になることを確認した。さらに、方向分離を双曲型方程式にTemporal Blockingによる時間積分方向のデータ再利用にキャッシュの利用を促進する計算アルゴリズムを導入を検討した。
    この段階で本基盤研究(A)を包含する基盤研究(S)の採択が決定し、以降の研究遂行を基盤研究(S)で行うこととした。

  • 高次精度パラメトリック時空間モデルによる機械と流体の相互作用解析手法の開発

    日本学術振興会  科学研究費助成事業 若手研究(B)

    研究期間:

    2012年04月
    -
    2015年03月
     

    滝沢 研二

     概要を見る

    本研究は、機械と流体の相互作用を解析するための計算手法の開発である。流体の解析手法はこれまでに多く研究されてきており一定の成果を上げている。本研究の特徴は、この流体解析と周辺機械が起こす時間変化という空間のみならず時間のモデリングを行う点である。
    ここでは、3つの項目について取り組んだ。1つ目は運動方程式に着目し加速度が連続である条件を利用した時刻データの滑らかな記述手法の考案、2つ目は、弁の開閉のような空間のトポロジーが変わる問題を高精度に、そして高効率に、3つ目は回転体のようにそれ自身がトポロジーを変更せずとも、高精度な流体解析を実現するための格子を捩れずに解析する手法の考案である。

  • 多モーメント手法による多目的CFDコアの開発

    日本学術振興会  科学研究費助成事業 基盤研究(B)

    研究期間:

    2007年
    -
    2009年
     

    青木 尊之, 内海 隆行, 今井 陽介, 小林 宏充, 滝沢 研二

     概要を見る

    次世代の流体解析(CFD)において、流体方程式を格子点上の値、線積分平均値、面積分、体積積分平均値を従属変数として解く多モーメント手法が高精度かつ安定な計算を行うために有効である。直交格子に適合細分化格子法を導入することで解像度制御を行い、保存形IDO法による圧縮性流体計算、非圧縮性流体計算、乱流計算、多相流計算などの様々な流体問題に適用できる高性能な計算コアを開発する。

  • 荒天下を航走する船舶の動揺ならびに船体弾性応答計算法の研究開発

    日本学術振興会  科学研究費助成事業 基盤研究(A)

    研究期間:

    2005年
    -
    2007年
     

    谷澤 克治, 滝沢 研二, 柴田 和也, 南 佳成, 柏木 正, 矢部 孝, 小川 剛孝, 南 真紀子

     概要を見る

    格子を用いる計算法の研究では、17年度は計算手法として非保存形のCIP法をベースにしていたが、自由表面の計算等で保存性が問題となったため、18年度には保存形ベースのIDO法を開発し、こちらに移行した。これにより、計算精度(特に流体力の力積)を向上させることができた。また、界面捕獲法にはTHINC法を導入し、甲板上部へ流れる流体の体積保存を行うことができるようになった。19年度は保存系IDO法と直交格子を用いて、境界の無い問題、四角い境界の問題を使った数値的ベンチーマークテスト、四角以外の境界の計算法の確立(物体境界での保存則の補償)、自由界面問題への適応、3次元化、スペクトル法との比較(DNS、LES化)と段階的に研究を進め、3次元での自由表面問題への適応を可能にした。特にDNSの計算では、同じ精度の非保存形IDO法と比べ、保存性、ロバスト性、計算精度の全てにおいて、極めて良好な結果を得た。(スペクトル法と比較できるオーダーの精度を達成)また、本研究では並列化を重視し、マルチカラーSORの開発や、マルチグリッド法を本手法に合わせて開発した。並列化性能の検証を目的として、東工大のスパコン上で512CPUを使った計算を行った結果、キャッシュ効果によるスーパーリニアに計算が効率化できることが確認できた。
    一方、格子を用いない計算法(MPS法)の研究では、17年度は船体大振幅動揺によって発生する船内液体タンクの流体衝撃減少、スロッシングの計算にMPS法を適応したが、船体表面に働く圧力を求める際、計算結果に現れる圧力振動が大きな問題となっていた。18年度は格子を用いる計算法を部分的に取り入れ、圧力計算点が計算の進行と共に移動しない方法を用いることで、圧力振動を効果的に抑える方法を開発した。19年度はタンク内の流れに限定してきた粒子法を、船外の波浪場の計算にも適応し、荒天波浪中を航走する船舶のシミュレーションプログラムを開発した。本プログラムにより、大波の中を航走する船舶の運動、船体に働くスラミング衝撃荷重、甲板上への波の打ち込み等の計算を実施した結果、安定して計算が可能であることを確認すると共に、ストリップ法等の線形理論に基づく計算法との比較を行い、計算結果の妥当性を確認することができた。

  • 荒天下を航走する船舶の動揺ならびに船体弾性応答計算法の研究開発

    科学研究費助成事業(独立行政法人海上技術安全研究所)  科学研究費助成事業(基盤研究(A))

  • 多モーメント手法による多目的CFDコアの開発

    科学研究費助成事業(東京工業大学)  科学研究費助成事業(基盤研究(B))

  • 高次精度パラメトリック時空間モデルによる機械と流体の相互作用解析手法の開発

    科学研究費助成事業(早稲田大学)  科学研究費助成事業(若手研究(B))

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