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Your search keyword '"Skew-symmetric form"' showing total 2 results
Start Over Descriptor "Skew-symmetric form" Journal computers & fluids
2 results on '"Skew-symmetric form"'

1. Impact of wall modeling on kinetic energy stability for the compressible Navier-Stokes equations

Author

Steven H. Frankel, Vikram Singh, and Jan Nordström

Subjects
General Computer Science, FOS: Physical sciences, Strömningsmekanik och akustik, Slip (materials science), Kinetic energy, 01 natural sciences, Stability (probability), 010305 fluids & plasmas, Physics::Fluid Dynamics, Stress (mechanics), Discontinuous Galerkin method, 0103 physical sciences, FOS: Mathematics, Mathematics - Numerical Analysis, Boundary value problem, 0101 mathematics, Discontinuous Galerkin, Skew-symmetric form, Stability, Summation-by-parts, Wall modelling, Physics, Fluid Mechanics and Acoustics, Turbulence, Fluid Dynamics (physics.flu-dyn), General Engineering, Numerical Analysis (math.NA), Physics - Fluid Dynamics, Mechanics, Computational Physics (physics.comp-ph), 010101 applied mathematics, Norm (mathematics), Physics - Computational Physics
Abstract

Affordable, high order simulations of turbulent flows on unstructured grids for very high Reynolds number flows require wall models for efficiency. However, different wall models have different accuracy and stability properties. Here, we develop a kinetic energy stability estimate to investigate stability of wall model boundary conditions. Using this norm, two wall models are studied, a popular equilibrium stress wall model, which is found to be unstable and the dynamic slip wall model which is found to be stable. These results are extended to the discrete case using the Summation by parts (SBP) property of the discontinuous Galerkin method. Numerical tests show that while the equilibrium stress wall model is accurate but unstable, the dynamic slip wall model is inaccurate but stable., Accepted in Computers and Fluids

Published
2021
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2. On the use of split forms and wall modeling to enable accurate high-Reynolds number discontinuous Galerkin simulations on body-fitted unstructured grids.

Author

Singh, Vikram and Frankel, Steven

Subjects
*REYNOLDS number, *TURBULENT flow, *FLOW simulations, *GALERKIN methods
Abstract

• Demonstrate utility of using split forms for stability. • Combine wall modeling with split form. • Computations validating ILES capabilities of split form. • Stable computations at high Reynolds' number on coarse mesh. The discontinuous Galerkin (DG) method is a promising numerical method to enable high- order simulations of turbulent flows associated with complex geometries. The method allows implicit large eddy simulations, however affordable simulations of very high Reynolds' number flows require wall models. In addition, high Reynolds' number typically implies the simulations are under-resolved. This becomes problematic as a high polynomial order may lead to aliasing instabilities on coarse grids, often leading to blow-up. Split formulations, first introduced in the finite-difference community, are a promising approach to address this problem. The present study shows that split forms and wall models can be used to enable the discontinuous Galerkin method to do very high Reynolds' number simulations on unstructured grids. [ABSTRACT FROM AUTHOR]

Published
2020
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