# transient laminar free-convection flow

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 August 17, 2016, 11:30 transient laminar free-convection flow #1 Senior Member   A. Min Join Date: Mar 2015 Posts: 305 Rep Power: 10 Hi dears I want to solve a transient laminar free-convection flow and heat transfer of water around a cylinder. 1- I select buoyantBussinesqPimpleFoam. Is it correct? 2- I solved it but the results are wrong! i.e. I have very small amount of velocity! in order of 10^-9 !! Whats the problem? 3- If I solve my problem by the assumption of turbulent flow, it will give me correct answers!! - my openFoam version: 2.3.1 - endtime=1000 - deltat=1, 0.01, 0.001 (non of them gave me correct answer) - div schemes: Gauss linear, bounded Gauss linear, bounded Gauss linearUpwind(non of them gave me correct answer) FvSolution: solvers { p_rgh { solver PCG; preconditioner DIC; tolerance 1e-8; relTol 0.01; } p_rghFinal { \$p_rgh; relTol 0; } "(U|T|k|epsilon|R)" { solver PBiCG; preconditioner DILU; tolerance 1e-6; relTol 0.1; } "(U|T|k|epsilon|R)Final" { \$U; relTol 0; } } PIMPLE { momentumPredictor no; nOuterCorrectors 1; nCorrectors 2; nNonOrthogonalCorrectors 0; pRefCell 0; pRefValue 0; } relaxationFactors { fields { } equations { "(U|T|k|epsilon|R)" 0.9; "(U|T|k|epsilon|R)Final" 0.9; } } FvSchems: ddtSchemes { default Euler; } gradSchemes { default Gauss linear; } divSchemes { default none; //vanleer; //bounded Gauss upwind; linearUpwind; div(phi,U) bounded Gauss linearUpwind grad(U); div(phi,T) bounded Gauss linearUpwind grad(T); div(phi,k) bounded Gauss linearUpwind; div(phi,epsilon) bounded Gauss linearUpwind; div(phi,R) bounded Gauss linearUpwind; div(R) bounded Gauss linearUpwind; div((nuEff*dev(T(grad(U))))) Gauss linear; } laplacianSchemes { default Gauss linear corrected; } interpolationSchemes { default linear; } snGradSchemes { default corrected; } fluxRequired { default no; p_rgh ; }

 Tags flow, free-convection, laminar, openfoam, transient