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Title: OpenACC acceleration of an unstructured CFD solver based on a reconstructed discontinuous Galerkin method for compressible flows

Here, an OpenACC directive-based graphics processing unit (GPU) parallel scheme is presented for solving the compressible Navier–Stokes equations on 3D hybrid unstructured grids with a third-order reconstructed discontinuous Galerkin method. The developed scheme requires the minimum code intrusion and algorithm alteration for upgrading a legacy solver with the GPU computing capability at very little extra effort in programming, which leads to a unified and portable code development strategy. A face coloring algorithm is adopted to eliminate the memory contention because of the threading of internal and boundary face integrals. A number of flow problems are presented to verify the implementation of the developed scheme. Timing measurements were obtained by running the resulting GPU code on one Nvidia Tesla K20c GPU card (Nvidia Corporation, Santa Clara, CA, USA) and compared with those obtained by running the equivalent Message Passing Interface (MPI) parallel CPU code on a compute node (consisting of two AMD Opteron 6128 eight-core CPUs (Advanced Micro Devices, Inc., Sunnyvale, CA, USA)). Speedup factors of up to 24× and 1.6× for the GPU code were achieved with respect to one and 16 CPU cores, respectively. The numerical results indicate that this OpenACC-based parallel scheme is an effective and extensible approachmore » to port unstructured high-order CFD solvers to GPU computing.« less
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [2]
  1. Idaho National Lab. (INL), Idaho Falls, ID (United States)
  2. North Carolina State Univ., Raleigh, NC (United States)
Publication Date:
OSTI Identifier:
1249553
Report Number(s):
INL/JOU--15-34041
Journal ID: ISSN 0271-2091
Grant/Contract Number:
AC07-05ID14517
Type:
Accepted Manuscript
Journal Name:
International Journal for Numerical Methods in Fluids
Additional Journal Information:
Journal Volume: 78; Journal Issue: 3; Journal ID: ISSN 0271-2091
Publisher:
Wiley
Research Org:
Idaho National Laboratory, Idaho Falls, ID (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
97 MATHEMATICS AND COMPUTING GPU computing; OpenACC; CUDA; discontinuous Galerkin; WENO; compressible flow; Navier-Stokes equations