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Multigrid Preconditioning for a Space-Time Spectral-Element Discontinuous-Galerkin SolverIn this work we examine a multigrid preconditioning approach in the context of a high- order tensor-product discontinuous-Galerkin spectral-element solver. We couple multigrid ideas together with memory lean and efficient tensor-product preconditioned matrix-free smoothers. Block ILU(0)-preconditioned GMRES smoothers are employed on the coarsest spaces. The performance is evaluated on nonlinear problems arising from unsteady scale- resolving solutions of the Navier-Stokes equations: separated low-Mach unsteady ow over an airfoil from laminar to turbulent ow. A reduction in the number of ne space iterations is observed, which proves the efficiency of the approach in terms of preconditioning the linear systems, however this gain was not reflected in the CPU time. Finally, the preconditioner is successfully applied to problems characterized by stiff source terms such as the set of RANS equations, where the simple tensor product preconditioner fails. Theoretical justification about the findings is reported and future work is outlined.
Document ID
20200000480
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Franciolini, Matteo
(Universities Space Research Association (USRA) Moffett Field, CA, United States)
Murman, Scott
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
January 21, 2020
Publication Date
January 6, 2020
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
ARC-E-DAA-TN76312
Meeting Information
Meeting: AIAA SciTech 2020
Location: Orlando, FL
Country: United States
Start Date: January 6, 2020
End Date: January 10, 2020
Sponsors: American Institute of Aeronautics and Astronautics (AIAA)
Funding Number(s)
CONTRACT_GRANT: NNH15CO48B
Distribution Limits
Public
Copyright
Public Use Permitted.
Technical Review
NASA Peer Committee
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