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trying why my runs diverge - simple case I built |
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October 28, 2023, 15:55 |
trying why my runs diverge - simple case I built
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#1 |
New Member
Join Date: Oct 2023
Posts: 5
Rep Power: 3 |
So I have the following case that I built, the mesh lis ok (used checkMesh), and developed the the required constants. However, when I run simpleFoam or foamRun, it starts to solve up to certain point and then it starts to produce nan.
For example, see below HTML Code:
[CODE]SmoothSolver: Solving for Ux, Initial residual = 0.91362581, Final residual = 9.1691167e-06, No Iterations 36 smoothSolver: Solving for Uy, Initial residual = 0.97344182, Final residual = 7.8785232e-06, No Iterations 34 smoothSolver: Solving for Uz, Initial residual = 0.99999992, Final residual = 8.4295095e-06, No Iterations 37 GAMG: Solving for p, Initial residual = 1, Final residual = nan, No Iterations 1000 time step continuity errors : sum local = nan, global = nan GAMG: Solving for p, Initial residual = nan, Final residual = nan, No Iterations 1000 time step continuity errors : sum local = nan, global = nan, cumulative = nan smoothSolver: Solving for epsilon, Initial residual = nan, Final residual = nan, No Iterations 1000 smoothSolver: Solving for k, Initial residual = nan, Final residual = nan, No Iterations 1000 ExecutionTime = 15.673765 s ClockTime = 15 s Courant Number mean: nan max: nan Time = 0.0469628s smoothSolver: Solving for Ux, Initial residual = nan, Final residual = nan, No Iterations 1000 smoothSolver: Solving for Uy, Initial residual = nan, Final residual = nan, No Iterations 1000 smoothSolver: Solving for Uz, Initial residual = nan, Final residual = nan, No Iterations 1000 [/CODE] |
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October 29, 2023, 14:08 |
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#2 |
Senior Member
Join Date: Apr 2020
Location: UK
Posts: 747
Rep Power: 14 |
Looks like you are trying to run as a transient simulation. Try changing over to steady state:
- in fvSchemes, change ddtSchemes default from Euler to steadyState - in fvSolution, comment out the PIMPLE section and add the following: Code:
SIMPLE { nNonOrthogonalCorrectors 0; consistent yes; residualControl { p 1e-2; U 1e-3; "(k|epsilon)" 1e-3; } } relaxationFactors { fields { p 0.3; } equations { U 0.7; k 0.7; epsilon 0.7; } } Now run with simpleFoam, and this should converge/behave nicely. Good luck! |
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