■Faculty | Department of Mechanical Engineering / Graduate School of Science and Engineering Research |

■Position | Lecturer |

■Degree | |

■Commentator Guide | https://www.kindai.ac.jp/meikan/471-hashimoto-tomohisa.html |

■URL | |

Last Updated :2020/04/03

- Optimized finite difference method with artificial dissipation for under-resolved unsteady incompressible flow computations using kinetically reduced local Navier-Stokes equations, T. Hashimoto, I. Tanno, T. Yasuda, Y. Tanaka, K. Morinishi, N. Satofuka, Computers and Fluids, Computers and Fluids, 184, 21 - 28, Apr. 2019 , Refereed
- Multi-GPU parallel computation of unsteady incompressible flows using kinetically reduced local Navier–Stokes equations, T. Hashimoto, T. Yasuda, I. Tanno, Y. Tanaka, K. Morinishi, N. Satofuka, 167, 215 - 220, May 2018 , Refereed
- Higher Order Numerical Simulation of Unsteady Viscous Incompressible Flows using Kinetically Reduced Local Navier-Stokes Equations on a GPU, T. Hashimoto, I. Tanno, T. Yasuda, Y. Tanaka, K. Morinishi, N. Satofuka, Computers and Fluids, Computers and Fluids, 110, 108 - 113, Mar. 2015 , Refereed
- Comparison of Local Computational Approaches for Unsteady Viscous Incompressible Flows, Nobuyuki Satofuka, Koji Morinishi, Itaru Tanno, Tomohisa Hashimoto, Takahiro Yasuda, Yoshihiro Tanaka, Computational Methods in Applied Sciences, Computational Methods in Applied Sciences, 34, 211 - 223, Jun. 2014 , Refereed
- Comparison of virtual flux Method on LBM and on other methods on a GPU, I. Tanno, T. Hashimoto, T. Yasuda, Y. Tanaka, K. Morinishi, N. Satofuka, Computers and Fluids, Computers and Fluids, 88, 822 - 825, Dec. 2013 , Refereed
- Simulation of doubly periodic shear layers using Kinetically Reduced Local Navier-Stokes equations on a GPU, T. Hashimoto, I. Tanno, Y. Tanaka, K. Morinishi, N. Satofuka, Computers and Fluids, Computers and Fluids, 88, 715 - 718, Dec. 2013 , Refereed
- Efficient simulation for incompressible turbulent flow using lattice Bolzmann model, T. Yasuda, T. Hashimoto, H. Minagawa, K. Morinishi, N. Satofuka, Procedia Engineering, Procedia Engineering, 61, 173 - 178, Jul. 2013 , Refereed
- Simulation of Turbulent Flow by Lattice Boltzmann Method and Conventional Method on a GPU, I. Tanno, T. Hashimoto, T. Yasuda, Y. Tanaka, K. Morinishi, N. Satofuka, Computers and Fluids, Computers and Fluids, 80, 453 - 458, Jul. 2013 , Refereed
- Computation of unsteady incompressible viscous flows using kinetically reduced local Navier-Stokes equations on a GPU, T. Hashimoto, I. Tanno, Y. Tanaka, K. Morinishi, N. Satofuka, Procedia Engineering, Procedia Engineering, 61, 63 - 69, Jul. 2013 , Refereed
- Computation of two-phase flow in flip-chip packaging using level set method, Tomohisa Hashimoto, Keiichi Saito, Koji Morinishi, Nobuyuki Satofuka, Lecture Notes in Computational Science and Engineering, Lecture Notes in Computational Science and Engineering, 74 LNCSE, 145 - 152, Jan. 2011 , RefereedSummary:In flip-chip packaging technology, the underfill encapsulation is one of the important processes to obtain a significant improvement in fatigue lifetime for the solder joints between IC chip and substrate. The advanced design of electronic devices aiming at the enhancement of the performance involves the increase of the number of solder bumps, smaller size of the IC chip and smaller gap height between IC chip and substrate. That leads to various problems caused by the flow behavior, such as voids in underfill and mis-placed IC chip. The numerical analysis is more and more strongly required for simulating the underfill flow behavior, including the condition of dispensing the underfill material on the substrate. In fact, it is desirable to predict the filling time, the final fillet shape formed around IC chip and the occurrence of air trap especially around the solder bump in the underfill process, considering the effect of contact angle, viscosity and surface tension of the underfill material for increasing the reliability of flip-chip packaging. © 2010 Springer.
- Computation of Shape and Drag of a Deformable Elastic Body under Fluid Dynamic Force, Computers and Fluids, Computers and Fluids, 38(7), 1361 - 1368, Aug. 2009 , Refereed
- Computation of shape and drag of a deforming elastic body under fluid dynamic force, Tomohisa Hashimoto, Koji Morinishi, Nobuyuki Satofuka, Computers and Fluids, Computers and Fluids, 38, 1361 - 1368, Aug. 2009 , RefereedSummary:This paper describes numerical simulations for the shape and its drag of an elastic body deforming under the fluid dynamic force. The simulations were carried out by coupling the Navier-Stokes equations and the equations of motion of the elastic body. The equations of motion are formulated for an elastic shell model which is composed of material particles connected with elastic springs and dampers. The relation between deforming elastic body shape in response to the fluid dynamic force and its drag force was investigated under the constraint of constant volume and fixed center of gravity of the elastic body for incompressible and compressible supersonic flows. In these simulations, an initial shape of the elastic body is a circular cylinder and starts deformation under the fluid dynamic force. © 2008 Elsevier Ltd. All rights reserved.
- Aerodynamic performance of a deforming elastic body in supersonic flow, Tomohisa Hashimoto, Koji Morinishi, Nobuyuki Satofuka, Computational Fluid Dynamics 2006 - Proceedings of the Fourth International Conference on Computational Fluid Dynamics, ICCFD 2006, Computational Fluid Dynamics 2006 - Proceedings of the Fourth International Conference on Computational Fluid Dynamics, ICCFD 2006, 855 - 860, Jan. 2009 , Refereed
- Numerical simulation of underfill flow in flip-chip packaging, Tomohisa Hashimoto, Keiichi Saito, Koji Morinishi, Nobuyuki Satofuka, Computational Fluid Dynamics 2008, Computational Fluid Dynamics 2008, 573 - 578, Jan. 2009 , Refereed
- Numerical Simulation of Conventional Capillary Flow and No-flow Underfill in Flip-chip Packaging, T. Hashimoto, S. Tanifuji, K. Morinishi, N. Satofuka, Computers and Fluids, Computers and Fluids, 37(5), 520 - 523, Jun. 2008 , Refereed
- Numerical Simulation about Shape and Drag of Two-dimensional Elastic Body Deformed under Fluid Dynamic Force, Transactions of the Japan Society of Mechanical Engineers, Transactions of the Japan Society of Mechanical Engineers, 72(713), 9 - 16, Jan. 2006 , Refereed
- Numerical Simulation for Motions of Two-dimensional Elastic Deformable Body in Fluid, Transactions of the Japan Society of Mechanical Engineers, Transactions of the Japan Society of Mechanical Engineers, 70(698), 2499 - 2506, Oct. 2004 , Refereed
- Numerical Simulation for Impact of Elastic Deformable Body against Rigid Wall under Fluid Dynamic Force, Third International Conference on Computational Fluid Dynamics (ICCFD3), Third International Conference on Computational Fluid Dynamics (ICCFD3), 375 - 380, Jul. 2004 , Refereed
- Fluid-largely Deformable Elastic Body Interaction Problem Using Overset Grid, T. Hashimoto, K. Morinishi, N. Satofuka, CFD Journal, CFD Journal, 13(2), 181 - 190, Jul. 2004 , Refereed
- Parallel Computation of Vortex-Induced Vibration of a Circular Cylinder Using Overset Grid, T. Hashimoto, K. Morinishi, N. Satofuka, Parallel Computational Fluid Dynamics 2002: New Frontiers and Multi-Disciplinary Applications, Parallel Computational Fluid Dynamics 2002: New Frontiers and Multi-Disciplinary Applications, 403 - 410, Apr. 2003 , RefereedSummary:© 2003 Elsevier B.V. All rights reserved. A parallel computational algorithm for overset grid using the data strucure of onedimensional listed type arrangement [1] has been developed for analyzing the flow field of complicated geometries. The parallel code is extended to dynamic problems of fluidstructure interaction. The procedure of parallel computation for moving overset grid according to the motions of structure is proposed and its performance is investigated for simulations of vortex-induced vibration of a circular cylinder. The present numerical results are compared with experimental data an d other numerical results.
- Parallel computation for the Composite Grid Approach., HASHIMOTO Tomohisa, MORINISHI Koji, SATOFUKA Nobuyuki, Transactions of the Japan Society of Mechanical Engineers Series C, Transactions of the Japan Society of Mechanical Engineers Series C, 67(663), 2649 - 2654, Nov. 2001 , RefereedSummary:The purpose of the study is to investigate practical advantages, a potential for low computer time and fast convergence as well as accuracy to a steady state solution, of a lower upper symmetric Gauss-Seidel implicit relaxation method using overset grid technique and develop an efficient parallel computational algorithm with a data structure by one dimensional array. This method is applied to viscous turbulent flows around multi element airfoils. Almost linear performance of the speedup ratio in parallel computing is attained up to 16PEs on the Hitachi SR2201 computer. Comparison of the numerical result with available experimental data shows good agreement.

- Unsteady incompressible flow simulations by an optimized centered finite difference scheme on Multi-GPU, 2018 05 15
- Multi-GPU parallel computation of unsteady incompressible flows using kinetically reduced local Navier-Stokes equations, HASHIMOTO Tomohisa, YASUDA Takahiro, TANNO Itaru, TANAKA Yoshihiro, MORINISHI Koji, SATOFUKA Nobuyuki, Parallel CFD 2017, 2017 05 15
- Comparison of artificial compressibility method with and without subiteration for unsteady flow, Itaru Tanno, Tomohisa Hashimoto, Takahiro Yasuda, Yoshihiro Tanaka, Koji Morinishi, Nobuyuki Satofuka, ICCFD9, 2016 07 15
- S1440106 Improvement of work efficiency using a dynamic scheduling system constructed in the plastic injection molding company, YAMAMOT Keiji, HASHIMOTO Tomohisa, KUNIMUNE Noriaki, TANIGAWA Yoshisada, HONMA Takeya, TAKAMI Satoshi, Mechanical Engineering Congress, Japan, 2015 09 13 Summary:Currently, in the plastic injection molding industry, the manufacturing of a wide variety of products in small quantities increases. High quality of products is strongly needed, reducing the cost and being shorter delivery time. However, many small-to-medium sized companies have difficulties in investing the expansion of equipment, and making the production planning according to the order status in an appropriate manner due to suffering from the shortage of workers. In this research, we addressed the improvement of the work efficiency, and are constructing the production management system that is adequate to the production planning in the plastic injection molding company. The dynamic scheduling system is constituted by the combination of a production scheduler available with free and production management software packages, to solve the problem that initial introduction costs are too much, although maintenance costs are necessary. Our approach is considered to be a promising case of the improvement of the work efficiency in a small-to-medium sized company.
- G011052 Unsteady Heat Conduction Analysis for Arbitrary Geometry on Cartesian Grid, HASHIMOTO Tomohisa, TANNO Itaru, YASUDA Takahiro, TANAKA Yoshihiro, MORINISHI Koji, SATOFUKA Nobuyuki, Mechanical Engineering Congress, Japan, 2013 09 08 Summary:CAE is an important tool for designing the mold in injection molding and has been used extensively. The filling, packing and cooling stages in injection molding, as well as the warpage after ejection can be simulated. The purpose of this study is to develop a numerical method for solving the incompressible Navier-Stokes equations and the heat conduction equation simultaneously on a Cartesian grid. For computing unsteady incompressible viscous flows, we confirmed that kinetically reduced local Navier-Stokes (KRLNS) equations is a promising method in terms of accuracy, efficiency and the capability to capture the correct transient behavior without sub-iterations. In this paper, the numerical simulations of unsteady heat conduction were carried out by using virtual flux method (VFM), which can treat arbitrary geometries on a Cartesian grid. The two types of boundary conditions were specified. The numerical solutions were compared with those obtained theoretically. The good agreement was obtained.
- G607 Numerical simulation of flow in high Reynolds number region using quasi-equilibrium lattice Boltzmann model : Effect of the ratio of bulk viscosity to kinematic viscosity, YASUDA Takahiro, MINAGAWA Hisato, HASHIMOTO Tomohisa, TANNO Itaru, TANAKA Yoshihiro, MORINISHI Koji, Satofuka Nobuyuki, Fluids engineering conference ..., 2012 11 16 Summary:Quasi-equilibrium Lattice Boltzmann model (QELBM) has been developed in order to get stable solution at high Reynolds number flow simulation by tuning viscosity ratio, namely, the ratio of bulk viscosity and kinematic viscosity. QELBM uses only two relaxation times and does not need to solve non-linear equation at each grid point to enhance stability, thus the algorithm is simpler than Multi-Relaxation Time model and Entropic Lattice Boltzmann model. However, there is degree of freedom for determining the viscosity ratio and the effect of viscosity ratio on the results has not been known yet. In this study, we investigate the region of viscosity ratio where the calculation becomes stable and the effect of viscosity ratio on flow field in various Reynolds numbers and Mach numbers.
- G010021 Simulation of Duct Flows using Kinetically Reduced Local Navier-Stokes Equations and Virtual Flux Method, HASHIMOTO Tomohisa, TANNO Itaru, YASUDA Takahiro, TANAKA Yoshihiro, MORINISHI Koji, SATOFUKA Nobuyuki, Mechanical Engineering Congress, Japan, 2012 09 09 Summary:In our previous study, kinetically reduced local Navier-Stokes (KRLNS) equations was applied for simulation of two-dimensional (2-D) unsteady incompressible flow problems in order to demonstrate it's capability to capture the correct transient behavior. The numerical results obtained by the KRLNS equations were compared with those obtained by the artificial compressibility method (ACM), the lattice Boltzmann method (LBM) and the pseudo-spectral method (PSM). The divergence as a function of time in the KRLNS method was compared with that of the ACM. It was confirmed that the KRLNS method can capture the correct transient behavior without use of sub-iterations. In this paper, three-dimensional (3-D) numerical simulations of flows in a circular pipe are carried out by using the KRLNS equations and virtual flux method (VFM) proposed to treat the body with complicated geometries on a Cartesian grid. The solutions and computational time are compared with those obtained by the ACM using sub-iterations.
- Simulation of Decaying Two-dimentional Turbulence Using Kinetically Reduced Local Navier-Stokes Equations, ICCFD7, 2012 07
- Numerical Simulation of Underfill Encapsulation in Flip-chip Packaging, HASHIMOTO Tomohisa, SAITO Keiichi, MORINISHI Koji, SATOFUKA Nobuyuki, 日本流体力学会年会講演論文集, 2009 Summary:The objective of this research is to develop a computational fluid dynamics (CFD) solver for simulating underfill flow in flip-chip packaging, especially for designing the most optimum condition of solder joint performance. Two types of processes for applying the underfill encapsulant to the gap between IC chip and substrate are presented. It is found that the proposed analytical models have a considerable potential for predicting the underfill flow.
- Numerical Simulations of Two Dimensional Butterfly Model, HASHIMOTO Tomohisa, MORINISHI Koji, SATOFUKA Nobuyuki, The Computational Mechanics Conference, 2003 11 22 Summary:Numerical simulations of a pair of flexible wing flapping symmetrically in two-dimesional space including the effect of wing deformations elastically in response to the fluid-dynamic forces are carried out in order to investigate its contributions to the aerodynamic force production in flapping flight. A flexible wing of insect is formulated as an elastic membrane model using mass-spring with damping effect.

- GPU implementation of the lattice Boltzmann method and Virtual flux method, Itaru Tanno, Tomohisa Hashimoto, Takahiro Yasuda, Yoshihiro Tanaka, Koji Morinishi, Nobuyuki Satofuka, Nobuyuki Satofuka, ECCOMAS 2012 - European Congress on Computational Methods in Applied Sciences and Engineering, e-Book Full Papers, 7244, 7250, 2012 12 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84871624825&origin=inwardSummary:Lattice Boltzmann method (LBM) which is suitable for General Purpose Graphic Processing Unit (GPGPU) and Virtual flux method (VFM) which is one of a Cartesian grid method are implemented on a GPU. Flow around a circular cylinder was simulated by the coupling of LBM and VFM. Lengths of twin vortex behind the cylinder are compared. Present results are agreed with other researchers result. GPU acceleration of LBM and VFM is also examined. Present result evidently shows that a computational time of LBM and VFM on GPU was 17 times faster than that on one core of a CPU.
- Study on highly efficient numerical simulation of flow using thirteen velocity Quasi-equilibrium Lattice Boltzmann model, Takahiro Yasduda, Tomohisa Hashimoto, Itaru Tanno, Yoshihiro Tanaka, Hisato Minagawa, Koji Morinish, Nobuyuki Satofuka, ECCOMAS 2012 - European Congress on Computational Methods in Applied Sciences and Engineering, e-Book Full Papers, 6124, 6129, 2012 12 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84871633786&origin=inwardSummary:Quasi-equilibrium Lattice Boltzmann model (QELBM) has been developed in order to overcome disruptive non-linear instability occurring in the standard LBGK model and get stable solution at high Reynolds number flow simulation in recent years. In the computation using QELBM, 13 velocity model for 3-dimensional calculation can be used, thereby highly efficient computations of three dimensional flow in high Reynolds number region, which is important for industrial application such as flow around the automobile, are possible. However, the application of QELBM for 3-dimensonal flow has not been done yet, thus the detail about the advantage of QELBM over other methods is not known. In this study, we applied QELBM to lid-driven cubic cavity flow in Reynolds number Re = 100, 400 and 1000, liddriven velosity U = 0.1, and investigated the advantage of QELBM for the stability, accuracy and computational effort by comparing with 13 velocity MRT and 19 velocity LBGK model.
- Numerical simulation of unsteady flow around deforming elastic body under fluid dynamic force, T. Hashimoto, K. Morinishit, N. Satofuka, ECCOMAS 2004 - European Congress on Computational Methods in Applied Sciences and Engineering, 2004 12 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84893482956&origin=inwardSummary:This paper describes a numerical method for simulating fluid-structure interaction, especially fluid-elastic body interaction problem. A model is formulated for the elastic shell made of thin film, for example a balloon whose inside is filled with isothermal gas. The film model is composed of material particles connected with elastic springs and dashpots so that the film can be expand and contract with the effect of damped vibration under the fluid dynamic force. The model is first verified for damped free vibration of a cylindrical elastic shell in stationary fluid. Numerical simulations of incompressible unsteady flow around a moving and deforming elastic body in response to the fluid dynamic force are carried out by using the model. The model is extended to treat the impact of an elastic body against the rigid wall including the effect of friction under the fluid dynamic force. It is found that the proposed elastic body model could be useful for investigating the mechanism of the deformation of moving elastic shell.