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Bug in LES eddy viscosity GenEddyVis.C??-- compressible |
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January 12, 2013, 22:38 |
Bug in LES eddy viscosity GenEddyVis.C??-- compressible
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#1 |
Member
yijin Mao
Join Date: May 2010
Location: Columbia, MO
Posts: 62
Rep Power: 15 |
Here is the function return effective stress tensor term in momentum equation from GenEddyVis.C (OpenFOAM-2.1.1).
tmp<fvVectorMatrix> GenEddyVisc::divDevRhoBeff(volVectorField& U) const { return ( - fvm::laplacian(muEff(), U) - fvc::div(muEff()*dev2(T(fvc::grad(U)))) ); } my question is where is the term for the trace of the subgrid scale stresses? It should looks like this or others..., anyway, k them is missing, and I didn't see anywhere account for it. tmp<fvVectorMatrix> GenEddyVisc::divDevRhoBeff(volVectorField& U) const { return ( - fvm::laplacian(muEff(), U) - fvc::div(muEff()*dev2(T(fvc::grad(U)))) + 2.0/3.0*fvc::grad(rho()*k()) ); } My derivation is attached, please give me some suggestions? |
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January 17, 2013, 12:16 |
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#2 |
Member
Gregor Olenik
Join Date: Jun 2009
Location: http://greole.github.io/
Posts: 89
Rep Power: 16 |
Hi Edward,
as far as i know you can absorb the missing term into pressure by defining a new pressure as p*=p+p_SGS where p_SGS is -1/3*rho*k_SGS but following the argument of Erlebacher et. al 1991 (Toward the large-eddy simulation of compressible turbulent flows) p.159 the influence off the sgs pressure is neglectible compared to the thermodynamical pressure (for moderate Mach numbers). |
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