The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform

Giuseppe Pascazio - One of the best experts on this subject based on the ideXlab platform.

  • computing unsteady compressible flows using roe s Flux Difference Splitting scheme on gpus
    Computer Physics Communications, 2013
    Co-Authors: M. Tuttafesta, Gianpiero Colonna, Giuseppe Pascazio
    Abstract:

    Abstract A Roe’s Flux-Difference Splitting scheme has been implemented using the NVIDIA CUDA architecture and has been applied to solve the two-dimensional compressible Euler equations. Different standard test cases have been considered in order to estimate the speed-up of GPU computing with respect to CPU calculation. A detailed description of the kernel configuration has been provided and a theoretical analysis of the GPU execution time as a function of the number of threads managed by the kernels is also reported. The loss of performance has been fully described consequent to the use of zero-copy memory. Significant performance improvements have been obtained by using a more recent GPU and CUDA Toolkit. A test case on multi-GPU architecture has been presented in the domain decomposition approach.

  • Computing unsteady compressible flows using Roe’s Flux-Difference Splitting scheme on GPUs
    Computer Physics Communications, 2013
    Co-Authors: M. Tuttafesta, Gianpiero Colonna, Giuseppe Pascazio
    Abstract:

    Abstract A Roe’s Flux-Difference Splitting scheme has been implemented using the NVIDIA CUDA architecture and has been applied to solve the two-dimensional compressible Euler equations. Different standard test cases have been considered in order to estimate the speed-up of GPU computing with respect to CPU calculation. A detailed description of the kernel configuration has been provided and a theoretical analysis of the GPU execution time as a function of the number of threads managed by the kernels is also reported. The loss of performance has been fully described consequent to the use of zero-copy memory. Significant performance improvements have been obtained by using a more recent GPU and CUDA Toolkit. A test case on multi-GPU architecture has been presented in the domain decomposition approach.

Ryoichi S. Amano - One of the best experts on this subject based on the ideXlab platform.

  • On the Development of Turbomachine Blade Aerodynamic Design System
    International Journal for Computational Methods in Engineering Science and Mechanics, 2009
    Co-Authors: Ryoichi S. Amano
    Abstract:

    A turbomachine blade aerodynamic design process is proposed to design turbomachine blades. The design system, including a global optimization of through flow for whole machine and a local optimization of the airfoil design and airfoil section, stacks up. The airfoil generator code employs Bezier polynomial curves to produce smooth airfoil shapes. A meanline program combined with an optimizer was used to perform the global optimization. In the airfoil section design, for fast calculations of the airfoil pressure distributions a discrete vortex method is developed. A novel Navier-Stokes (N-S) solver is developed for further examination of the airfoil performance for final section design. The N-S code is used to obtain the blade-to-blade quasi-three-dimensional, turbulent, and viscous flow characteristics. The time-dependent N-S equations are discretized and integrated in a coupled manner based on a finite-volume formulation, as well as a Flux-Difference Splitting. The Flux-Difference Splitting method enable...

  • Flux-Splitting finite volume method for turbine flow and heat transfer analysis
    Computational Mechanics, 2001
    Co-Authors: Ryoichi S. Amano
    Abstract:

    A novel numerical method was developed to deal with the flow and heat transfer in a turbine cascade at both design and off-design conditions. The Navier–Stokes equations are discretized and integrated in a coupled manner. In the present method a time-marching scheme was employed along with the time-integration approach. The Flux terms are discretized based on a cell finite volume formulation as well as a Flux-Difference Splitting. The Flux-Difference Splitting makes the scheme rapid convergence and the finite volume technique ensure the governing equations for the conservation of mass, momentum and energy. A hybrid Difference scheme for quasi-three-dimensional procedure based on the discretized and integrated Navier–Stokes equations was incorporated in the code. The numerical method possesses the positive features of the explicit and implicit algorithms which provide a rapid convergence process and have a less stability constraint. The computed results were compared with other numerical studies and experimental data. The comparisons showed fairly good agreement with experiments.

  • Aerodynamics and Heat Transfer in a Turbine Blade at Design and Off-Design Angles of Incidence
    Volume 3: Heat Transfer; Electric Power; Industrial and Cogeneration, 2000
    Co-Authors: Ryoichi S. Amano
    Abstract:

    A novel numerical method was developed to deal with the studies of the aerodynamic and heat transfer of flow passing through blade cascades at both design and off-design conditions. The Navier-Stokes equations are discretized and integrated in a coupled manner in this study. The time-marching was achieved by using time integration approach in the present method. The Flux terms are discretized based on a cell finite volume formulation as well as a Flux-Difference Splitting. The Flux-Difference Splitting can ensure the scheme with rapid convergence and the finite volume technique can ensure the equation for the conservation of mass, momentum and energy. A hybrid Difference scheme for quasi-three-dimensional procedure based on the discretized and integrated Navier-Stokes equations as developed to study flow and heat transfer in turbine blade passages. The numerical method possesses the positive features of the explicit and implicit algorithms, providing a relatively rapid convergence process and having a less restricted stability constraint. The computed results were compared with other numerical study results and experiments and showed fairly good agreement.Copyright © 2000 by ASME

Thomas Heuzé - One of the best experts on this subject based on the ideXlab platform.

  • Simulation of impacts on elastic-viscoplastic solids with the Flux-Difference Splitting finite volume method applied to non-uniform quadrilateral meshes
    Advanced Modeling and Simulation in Engineering Sciences, 2018
    Co-Authors: Thomas Heuzé
    Abstract:

    The Flux-Difference Splitting finite volume method is here employed to perform numerical simulation of impacts on elastic-viscoplastic solids on bidimensional non-uniform quadrilateral meshes. The formulation is second order accurate in space through Flux limiters, embeds the corner transport upwind method, and uses a fractional-step method to compute the relaxation operator. Elastic-viscoplastic constitutive models falling within the framework of generalized standard materials in small strains are considered. Many test cases are proposed and two particular viscoplastic constitutive models are studied, on which comparisons with finite element solutions show a very good accuracy of the finite volume solutions, both on stresses and viscoplastic strains.

  • simulation of impacts on elastic viscoplastic solids with the Flux Difference Splitting finite volume method applied to non uniform quadrilateral meshes
    Advanced Modeling and Simulation in Engineering Sciences, 2018
    Co-Authors: Thomas Heuzé
    Abstract:

    The Flux-Difference Splitting finite volume method (Leveque in J Comput Phys 131:327–353, 1997; Leveque in Finite volume methods for hyperbolic problems. Cambridge: Cambridge University Press, 2002) is here employed to perform numerical simulation of impacts on elastic–viscoplastic solids on bidimensional non-uniform quadrilateral meshes. The formulation is second order accurate in space through Flux limiters, embeds the corner transport upwind method, and uses a fractional-step method to compute the relaxation operator. Elastic–viscoplastic constitutive models falling within the framework of generalized standard materials (Halphen and Nguyen in J Mech 14:667–688, 1975) in small strains are considered. Many test cases are proposed and two particular viscoplastic constitutive models are studied, on which comparisons with finite element solutions show a very good accuracy of the finite volume solutions, both on stresses and viscoplastic strains.

  • Simulation of impacts on elastic–viscoplastic solids with the Flux-Difference Splitting finite volume method applied to non-uniform quadrilateral meshes
    Advanced Modeling and Simulation in Engineering Sciences, 2018
    Co-Authors: Thomas Heuzé
    Abstract:

    The Flux-Difference Splitting finite volume method (Leveque in J Comput Phys 131:327–353, 1997 ; Leveque in Finite volume methods for hyperbolic problems. Cambridge: Cambridge University Press, 2002 ) is here employed to perform numerical simulation of impacts on elastic–viscoplastic solids on bidimensional non-uniform quadrilateral meshes. The formulation is second order accurate in space through Flux limiters, embeds the corner transport upwind method, and uses a fractional-step method to compute the relaxation operator. Elastic–viscoplastic constitutive models falling within the framework of generalized standard materials (Halphen and Nguyen in J Mech 14:667–688, 1975 ) in small strains are considered. Many test cases are proposed and two particular viscoplastic constitutive models are studied, on which comparisons with finite element solutions show a very good accuracy of the finite volume solutions, both on stresses and viscoplastic strains.

  • Numerical simulation of impacts on elastic-viscoplastic solids with the Flux-Difference Splitting finite volume method
    2017
    Co-Authors: Thomas Heuzé
    Abstract:

    A finite volume method is used and extended for the numerical simulation of impacts on elastic-viscoplastic solids with bidimensional curvilinear structured meshes. The formulation is based on the Flux-Difference Splitting method, has second order accuracy through Flux limiters, embeds the corner transport upwind method, and uses the second order accurate Strang Splitting method to handle the right hand side of the system of balance laws. The approach is here derived with a Chaboche-type elastic-viscoplastic solid within the small strain framework, and is illustrated on a problem of impact on a heterogeneous volume containing an inclusion. A comparison is performed with a finite element solution obtained with the finite element code Cast3M.

Li Yuan - One of the best experts on this subject based on the ideXlab platform.

  • Flux-Difference Splitting-based upwind compact schemes for the incompressible Navier–Stokes equations
    2016
    Co-Authors: Abdullah Shah, Li Yuan
    Abstract:

    Third-order and fifth-order upwind compact finite Difference schemes based on Flux-Difference Splitting are proposed for solving the incompressible Navier–Stokes equations in conjunction with the artificial compressibility (AC) method. Since the governing equations in the AC method are hyperbolic, Flux-Difference Splitting (FDS) originally developed for the compressible Euler equations can be used. In the present upwind compact schemes, the split derivatives for the convective terms at grid points are linked to the Differences of split Fluxes between neighboring grid points, and these Differences are computed by using FDS. The viscous terms are approximated with a sixth-order central compact scheme. Comparisons with 2D benchmark solutions demonstrate that the present compact schemes are simple, efficient, an

  • Flux‐Difference Splitting‐based upwind compact schemes for the incompressible Navier–Stokes equations
    International Journal for Numerical Methods in Fluids, 2009
    Co-Authors: Abdullah Shah, Li Yuan
    Abstract:

    Third-order and fifth-order upwind compact finite Difference schemes based on Flux-Difference Splitting are proposed for solving the incompressible Navier-Stokes equations in conjunction with the artificial compressibility (AC) method. Since the governing equations in the AC method are hyperbolic, Flux-Difference Splitting (FDS) originally developed for the compressible Euler equations can be used. In the present upwind compact schemes, the split derivatives for the convective terms at grid points are linked to the Differences of split Fluxes between neighboring grid points, and these Differences are computed by using FDS. The viscous terms are approximated with a sixth-order central compact scheme. Comparisons with 2D benchmark solutions demonstrate that the present compact schemes are simple, efficient, and high-order accurate.

  • Flux Difference Splitting based upwind compact schemes for the incompressible navier stokes equations
    International Journal for Numerical Methods in Fluids, 2009
    Co-Authors: Abdullah Shah, Li Yuan
    Abstract:

    Third-order and fifth-order upwind compact finite Difference schemes based on Flux-Difference Splitting are proposed for solving the incompressible Navier-Stokes equations in conjunction with the artificial compressibility (AC) method. Since the governing equations in the AC method are hyperbolic, Flux-Difference Splitting (FDS) originally developed for the compressible Euler equations can be used. In the present upwind compact schemes, the split derivatives for the convective terms at grid points are linked to the Differences of split Fluxes between neighboring grid points, and these Differences are computed by using FDS. The viscous terms are approximated with a sixth-order central compact scheme. Comparisons with 2D benchmark solutions demonstrate that the present compact schemes are simple, efficient, and high-order accurate.

  • a third order upwind compact scheme on curvilinear meshes for the incompressible navier stokes equations
    2008
    Co-Authors: Abdullah Shah, Hong Guo, Li Yuan
    Abstract:

    This paper presents a new version of the upwind compact finite Difference scheme for solving the incompressible Navier-Stokes equations in generalized curvilinear coordinates. The artificial compressibility approach is used, which transforms the elliptic-parabolic equations into the hyperbolic-parabolic ones so that Flux Difference Splitting can be applied. The convective terms are approximated by a third-order upwind compact scheme implemented with Flux Difference Splitting, and the viscous terms are approximated by a fourth-order central compact scheme. The solution algorithm used is the Beam-Warming approximate factorization scheme. Numerical solutions to benchmark problems of the steady plane Couette-Poiseuille flow, the liddriven cavity flow, and the constricting channel flow with varying geometry are presented. The computed results are found in good agreement with established analytical and numerical results. The third-order accuracy of the scheme is verified on uniform rectangular meshes. AMS subject classifications: 76D05, 65N06

Mohammad Jafar Kermani - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of inviscid and viscous transonic flow field in VKI gas turbine blade cascade
    Alexandria Engineering Journal, 2014
    Co-Authors: S.a. Moshizi, A. Madadi, Mohammad Jafar Kermani
    Abstract:

    Abstract In this paper, the viscous and inviscid flow fields of a gas turbine blade cascade are investigated. A two-dimensional CFD solver is developed to simulate the flow field through VKI blade cascade. A high resolution Flux Difference Splitting scheme of Roe is applied to discretize the convective part of Navier–Stokes equations. Baldwin Lomax (BL) model is used to account for turbulent effects on the viscous flow field of the blade cascade. For validation of the code, the flow field was solved by Ansys Fluent commercial software. The flow solution was done by third order Flux Difference Splitting scheme of Roe and k – ω turbulence model. The findings show that the high turbulent and the shock creation in the flow field, lead to the same results in viscous and inviscid flows. Also, the results show that the grid and solver’s focus must be on the precise prediction of the shock effects, when the shock is occurred in the domain.