Vorticity-Preserving Artificial Dissipation Model for Vortical Wake Prediction

Vorticities shed from a bluff body normally form one or several streamwise vortical flows. These vortical flows can last for long distances downstream. Accurate prediction of these vortical flows has always been a challenge to computational fluid dynamics. The numerically predicted vorticity has the...

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Bibliographic Details
Published in:AIAA journal 2008-09, Vol.46 (9), p.2377-2383
Main Authors: Sung, Chao-Ho, Rhee, Bong, Shih, T. M
Format: Article
Language:English
Subjects:
Energy dissipation
Exact sciences and technology
Fluid dynamics
Fundamental areas of phenomenology (including applications)
Physics
Rotational flow and vorticity
Separated flows
Simulation
Turbulent flow
Turbulent flows, convection, and heat transfer
Viscosity
Wakes
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Summary:Vorticities shed from a bluff body normally form one or several streamwise vortical flows. These vortical flows can last for long distances downstream. Accurate prediction of these vortical flows has always been a challenge to computational fluid dynamics. The numerically predicted vorticity has the tendency to dissipate prematurely. There are several reasons for premature dissipation of the predicted vorticity in the wake: 1) numerical truncation error, 2) excessive eddy viscosity introduced by turbulence models, and 3) artificial dissipation added to maintain numerical stability for complex flows. A new vorticity-preserving artificial-dissipation model (VPAD) is developed to minimize the premature dissipation of the predicted vorticity. VPAD achieves the goal of maintaining numerical stability while minimizing the premature dissipation of vorticity. Anticipating premature dissipation of vorticity, the vorticity-confinement term generates new vorticity to be put back into the flow region where vorticities are generated by the flow physics. In this manner, realistic vortical flow can be simulated by a small number of grid cells and tracked for long distances downstream.
ISSN:0001-1452
1533-385X
DOI:10.2514/1.32971