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May 18, 2022, 04:48 |
How to get convergence with simpleFoam?
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Denny Mathew Alex
Join Date: Mar 2022
Location: Essen, Germany
Posts: 2
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Hello Everyone 😊,
I am Denny and I am new to OpenFoam. I am learning OpenFoam by simulating a flow inside a rectangular chamber with simpleFoam solver. The boundaries are shown in the figures (inlet-Green, outlet-Red, wall-Blue). The geometry was created using Salome and mesh was generated using snappyHexMesh (only castellated Mesh part is True). Using the checkMesh, the quality of the mesh is OK. I ran the simulation to 2000 and 6000 time steps with delta t of 1 but could not achieve convergence. I have attached the velocity plot for time steps 1802 and 1902. I have pasted the boundary condition U and p, controlDict, fvSchemes, fvSolution below. What are the steps to be taken to get a good convergence in this case? Thank you for your help 😊. -------------------- U -------------------------------- internalField uniform (0 0 0); boundaryField { inlet { type fixedValue; value uniform (1 0 0); } outlet { type zeroGradient; value uniform (0 0 0); } wall { type noSlip; value uniform (0 0 0); } } ---------------- p ---------------------------- internalField uniform 0; boundaryField { inlet { type zeroGradient; } outlet { type fixedValue; value uniform 0; } wall { type zeroGradient; } } --------------------- controlDict ------------------------ application simpleFoam; startFrom startTime; startTime 1; stopAt endTime; endTime 6000; deltaT 1; writeControl timeStep; writeInterval 100; purgeWrite 0; writeFormat ascii; writePrecision 6; writeCompression off; timeFormat general; timePrecision 6; runTimeModifiable true; --------------- fvSchemes --------------------- ddtSchemes { default steadyState; } gradSchemes { default Gauss linear; } divSchemes { default none; div(phi,U) bounded Gauss upwind; div((nuEff*dev2(T(grad(U))))) Gauss linear; } laplacianSchemes { default Gauss linear corrected; } interpolationSchemes { default linear; } snGradSchemes { default corrected; } ------------------- fvSolution --------------------- solvers { p { solver GAMG; tolerance 1e-06; relTol 0.1; smoother GaussSeidel; } U { solver smoothSolver; smoother symGaussSeidel; tolerance 1e-05; relTol 0.1; } } SIMPLE { nNonOrthogonalCorrectors 0; nCorrectors 3; consistent yes; residualControl { p 1e-2; U 1e-3; } } relaxationFactors { fields { p 1; } equations { U 0.9; // 0.9 is more stable but 0.95 more convergent } } |
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