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March 6, 2024, 08:23 |
p equation error when restart calculation
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#1 |
New Member
wlz
Join Date: Mar 2024
Posts: 3
Rep Power: 2 |
When I use an FGM solver in OpenFOAM to calculate an LES case, I found that if I calculate without interrupting, the result will be right. But whenever I restart the calculation from my latest result, the p equation will be extremely strange from the first iteration and the initial residual will be close to 1. I am very certain that the p feild of the result I restart calculation from has no problem.
I am very confused about this situation. I will appreciate it very much if someone can help me haddle this problem. I attach a txt containing part of my output file. |
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March 6, 2024, 08:28 |
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#2 |
New Member
wlz
Join Date: Mar 2024
Posts: 3
Rep Power: 2 |
If there is a need to view my case or solver, I will upload them.
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March 6, 2024, 09:07 |
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#3 |
New Member
wlz
Join Date: Mar 2024
Posts: 3
Rep Power: 2 |
here is my fvscheme file
ddtSchemes { default backward; } gradSchemes { default cellLimited Gauss linear 1; grad(U) cellLimited Gauss linear 1; } divSchemes { default none; div(phi,U) Gauss linearUpwindV grad(U); div(phi,k) Gauss upwind; div(phi,epsilon) Gauss upwind; div((nuEff*dev(T(grad(U))))) Gauss linear; //added for FGMFoam: div(phi,Z) Gauss upwind; div(phi,PV) Gauss upwind; div(phi,varZ) Gauss upwind; div(phi,varPV) Gauss upwind; div(phi,K) Gauss upwind; div(phi,Yi_h) Gauss limitedLinear 1; div(phi,nuTilda) Gauss limitedLinear 1; div((muEff*dev2(T(grad(U))))) Gauss linear; div(((rho*nuEff)*dev2(T(grad(U))))) Gauss linear; div(phid,p) Gauss limitedLinear 1; } laplacianSchemes { default Gauss linear limited 1; } interpolationSchemes { default linear; } snGradSchemes { default limited1; } fluxRequired { default no; p; } and fvSolution file solvers { "(rho|rhoFinal)" { solver smoothSolver; smoother GaussSeidel; tolerance 1e-7; relTol 0; nSweeps 1; }; p { solver GAMG; tolerance 1e-8; relTol 0.1; smoother GaussSeidel; cacheAgglomeration true; nCellsInCoarsestLevel 10; agglomerator faceAreaPair; mergeLevels 1; } pFinal { $p; tolerance 1e-8; relTol 0; } pd { solver PCG; preconditioner DIC; tolerance 1e-8; relTol 0; } pdFinal { $p; tolerance 1e-8; relTol 0; } "(U|h|Z|PV|k|epsilon|varZ|varPV)" { solver PBiCG; preconditioner DILU; tolerance 1e-7; relTol 0.01; } "(U|h|Z|PV|k|epsilon|varZ|varPV)Final" { $U; relTol 0; } Yi { $hFinal; } } |
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March 12, 2024, 12:59 |
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#4 |
Senior Member
Join Date: Apr 2020
Location: UK
Posts: 668
Rep Power: 14 |
Hmmm ... it looks like the normalisation factor has changed on restart (remember that all of the residuals are normalised - refer to https://doc.cfd.direct/notes/cfd-gen...x130-166004r11). Not sure why this is happening, but it is occurring on just the first PIMPLE iteration, so shouldn't affect your solution ...
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