# Vortex Street with pisoFoam

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 June 10, 2011, 09:00 Vortex Street with pisoFoam #1 New Member   Join Date: Dec 2010 Posts: 2 Rep Power: 0 Hello people... I am fairly new to CFD and OpenFOAM, so I am not very sure about some results I am getting while simulating a vortex street with a flow around a cylinder. I was asked to use pisoFoam with laminar flow, and simulate a given mesh (with the cylinder) at Re=20, Re=200 (the vortex street should appear here) and Re=2000. At Re=20, I had no problems with convergence, with 8000 Iterations my residuals were below 10E-5. However at Re=200 and at Re=2000 the residuals oscillate asymptotically. Example: Re=200 Uploaded with ImageShack.us I would like to know whether this behaviour in my residuals is normal for vortex street calculations, or if I am really having some problems of some other kind. Ah, and I forgot to say... Courant-Nr<1 ... :/ Code: ```ddtSchemes { default Euler; } gradSchemes { default Gauss linear; grad(p) Gauss linear; grad(U) Gauss linear; } divSchemes { default none; div(phi,U) Gauss limitedLinearV 1; div(phi,k) Gauss limitedLinear 1; div(phi,epsilon) Gauss limitedLinear 1; div(phi,R) Gauss limitedLinear 1; div(R) Gauss linear; div(phi,nuTilda) Gauss limitedLinear 1; div((nuEff*dev(grad(U).T()))) Gauss linear; } laplacianSchemes { default none; laplacian(nuEff,U) Gauss linear corrected; laplacian((1|A(U)),p) Gauss linear corrected; laplacian(DkEff,k) Gauss linear corrected; laplacian(DepsilonEff,epsilon) Gauss linear corrected; laplacian(DREff,R) Gauss linear corrected; laplacian(DnuTildaEff,nuTilda) Gauss linear corrected; } interpolationSchemes { default linear; interpolate(U) linear; } snGradSchemes { default corrected; } fluxRequired { default no; p ; }``` Code: ```solvers { p { solver PCG; preconditioner DIC; tolerance 1e-06; relTol 0.1; } pFinal { solver PCG; preconditioner DIC; tolerance 1e-06; relTol 1e-4; } U { solver PBiCG; preconditioner DILU; tolerance 1e-05; relTol 0; } } PISO { nCorrectors 3; nNonOrthogonalCorrectors 0; pRefCell 0; pRefValue 0; }```