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-   -   calculation diverge after continue to run (https://www.cfd-online.com/Forums/openfoam/75525-calculation-diverge-after-continue-run.html)

 zhajingjing April 28, 2010 04:35

calculation diverge after continue to run

Hi，everyone

Recently I find that when I continue to run my case(eg, I calculated my case for 20s last time, now I modified the ebdTime to be 40,so I continue running), the calculation diverge. I try several cases, they all fail like this. This phenomenon never happened before. Does anyone meet this problem?

you see,
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 25

Selecting dynamicFvMesh dynamicMotionSolverFvMesh
Selecting motion solver: displacementLaplacian
water depth 0.6
wave type linearWave
wave omega 6.283185
wave height 0.02
wave number 4.084595
w=1.836603
piston stroke 0.005444834
Selecting motion diffusion: inverseDistance

Selecting incompressible transport model Newtonian
Selecting incompressible transport model Newtonian
Selecting RAS turbulence model laminar
time step continuity errors : sum local = 1.444482e-08, global = 1.435022e-08, cumulative = 1.435022e-08
DICPCG: Solving for pcorr, Initial residual = 1, Final residual = 7.714203e-08, No Iterations 140
DICPCG: Solving for pcorr, Initial residual = 3.427171e-09, Final residual = 3.427171e-09, No Iterations 0
time step continuity errors : sum local = 1.114302e-15, global = 2.682517e-17, cumulative = 1.435022e-08
Courant Number mean: 0.01505891 max: 0.1339163

Starting time loop

Courant Number mean: 0.01505891 max: 0.1339163
Time = 25.002

linear Wave piston position is 4.293759e-07
DICPCG: Solving for cellDisplacementx, Initial residual = 0.9988885, Final residual = 9.096984e-08, No Iterations 383
DICPCG: Solving for cellDisplacementy, Initial residual = 0, Final residual = 0, No Iterations 0
Execution time for mesh.update() = 1.37 s
time step continuity errors : sum local = 1.434755e-08, global = -1.434755e-08, cumulative = 2.671165e-12
DICPCG: Solving for pcorr, Initial residual = 1, Final residual = 9.846891e-08, No Iterations 139
DICPCG: Solving for pcorr, Initial residual = 4.348726e-09, Final residual = 4.348726e-09, No Iterations 0
time step continuity errors : sum local = 1.41279e-15, global = -3.167157e-17, cumulative = 2.671133e-12
MULES: Solving for gamma
Liquid phase volume fraction = 0.5000462 Min(gamma) = -2.304434e-67 Max(gamma) = 1.000002
MULES: Solving for gamma
Liquid phase volume fraction = 0.5000011 Min(gamma) = -2.297683e-67 Max(gamma) = 1.000004
DICPCG: Solving for pd, Initial residual = 0.1916157, Final residual = 8.835227e-08, No Iterations 84
DICPCG: Solving for pd, Initial residual = 3.197623e-09, Final residual = 3.197623e-09, No Iterations 0
time step continuity errors : sum local = 4.759465e-10, global = 7.660377e-11, cumulative = 7.92749e-11
DICPCG: Solving for pd, Initial residual = 0.0006697087, Final residual = 8.359662e-08, No Iterations 49
DICPCG: Solving for pd, Initial residual = 8.633154e-08, Final residual = 8.633154e-08, No Iterations 0
time step continuity errors : sum local = 1.244683e-08, global = -3.657849e-09, cumulative = -3.578575e-09
ExecutionTime = 4 s ClockTime = 4 s

Courant Number mean: 0.06487583 max: 12.65412
Time = 25.004

linear Wave piston position is 1.718486e-06
DICPCG: Solving for cellDisplacementx, Initial residual = 0.8184182, Final residual = 9.771286e-08, No Iterations 382
DICPCG: Solving for cellDisplacementy, Initial residual = 0, Final residual = 0, No Iterations 0
Execution time for mesh.update() = 1.29 s
time step continuity errors : sum local = 1.244683e-08, global = -3.65785e-09, cumulative = -7.236424e-09
DICPCG: Solving for pcorr, Initial residual = 1, Final residual = 9.506461e-08, No Iterations 155
DICPCG: Solving for pcorr, Initial residual = 1.184242e-08, Final residual = 1.184242e-08, No Iterations 0
time step continuity errors : sum local = 1.183273e-15, global = -6.732176e-17, cumulative = -7.236424e-09
MULES: Solving for gamma
Liquid phase volume fraction = 0.4999555 Min(gamma) = -2.855421 Max(gamma) = 1.000028
MULES: Solving for gamma
Liquid phase volume fraction = 0.4999103 Min(gamma) = -11.62382 Max(gamma) = 12.92754
DICPCG: Solving for pd, Initial residual = 0.01535727, Final residual = 9.311828e-08, No Iterations 69
DICPCG: Solving for pd, Initial residual = 9.157189e-08, Final residual = 9.157189e-08, No Iterations 0
time step continuity errors : sum local = 1.405371e-08, global = -2.960173e-09, cumulative = -1.01966e-08
DICPCG: Solving for pd, Initial residual = 0.01140352, Final residual = 8.428359e-08, No Iterations 47
DICPCG: Solving for pd, Initial residual = 8.423795e-08, Final residual = 8.423795e-08, No Iterations 0
time step continuity errors : sum local = 1.305664e-08, global = 1.663829e-09, cumulative = -8.532768e-09
ExecutionTime = 6.32 s ClockTime = 7 s

Courant Number mean: 0.01547009 max: 0.9084346
Time = 25.006

linear Wave piston position is 3.867127e-06
DICPCG: Solving for cellDisplacementx, Initial residual = 0.6518518, Final residual = 7.768823e-08, No Iterations 382
DICPCG: Solving for cellDisplacementy, Initial residual = 0, Final residual = 0, No Iterations 0
Execution time for mesh.update() = 1.28 s
time step continuity errors : sum local = 1.305664e-08, global = 1.663829e-09, cumulative = -6.868939e-09
DICPCG: Solving for pcorr, Initial residual = 1, Final residual = 9.751944e-08, No Iterations 154
DICPCG: Solving for pcorr, Initial residual = 2.320168e-08, Final residual = 2.320168e-08, No Iterations 0
time step continuity errors : sum local = 1.273276e-15, global = 5.851911e-17, cumulative = -6.868939e-09
MULES: Solving for gamma
Liquid phase volume fraction = 0.4999103 Min(gamma) = -7.181216 Max(gamma) = 4.842551
MULES: Solving for gamma
Liquid phase volume fraction = 0.4999103 Min(gamma) = -6.619966 Max(gamma) = 2.834347
DICPCG: Solving for pd, Initial residual = 0.07596338, Final residual = 8.243381e-08, No Iterations 67
DICPCG: Solving for pd, Initial residual = 9.909663e-07, Final residual = 7.865661e-08, No Iterations 13
time step continuity errors : sum local = 1.07695e-09, global = 3.32348e-10, cumulative = -6.536591e-09
DICPCG: Solving for pd, Initial residual = 0.0440518, Final residual = 9.535207e-08, No Iterations 53
DICPCG: Solving for pd, Initial residual = 8.70003e-08, Final residual = 8.70003e-08, No Iterations 0
time step continuity errors : sum local = 1.295907e-09, global = -4.037227e-10, cumulative = -6.940313e-09
ExecutionTime = 8.72 s ClockTime = 9 s

Courant Number mean: 0.0212218 max: 7.507377
Time = 25.008

linear Wave piston position is 6.87496e-06
DICPCG: Solving for cellDisplacementx, Initial residual = 0.5380525, Final residual = 8.313747e-08, No Iterations 381
DICPCG: Solving for cellDisplacementy, Initial residual = 0, Final residual = 0, No Iterations 0
Execution time for mesh.update() = 1.27 s
time step continuity errors : sum local = 1.295907e-09, global = -4.037227e-10, cumulative = -7.344036e-09
DICPCG: Solving for pcorr, Initial residual = 1, Final residual = 9.740195e-08, No Iterations 151
DICPCG: Solving for pcorr, Initial residual = 1.216642e-08, Final residual = 1.216642e-08, No Iterations 0
time step continuity errors : sum local = 1.262291e-16, global = -3.557281e-18, cumulative = -7.344036e-09
MULES: Solving for gamma
Liquid phase volume fraction = 0.4999104 Min(gamma) = -6.494791 Max(gamma) = 4.573024
MULES: Solving for gamma
Liquid phase volume fraction = 0.4999104 Min(gamma) = -27.25873 Max(gamma) = 25.77633
DICPCG: Solving for pd, Initial residual = 0.1978681, Final residual = 8.198099e-08, No Iterations 77
DICPCG: Solving for pd, Initial residual = 3.041559e-09, Final residual = 3.041559e-09, No Iterations 0
time step continuity errors : sum local = 1.577804e-09, global = 3.218275e-10, cumulative = -7.022209e-09
DICPCG: Solving for pd, Initial residual = 0.09315195, Final residual = 8.495972e-08, No Iterations 83
DICPCG: Solving for pd, Initial residual = 9.250593e-10, Final residual = 9.250593e-10, No Iterations 0
time step continuity errors : sum local = 4.835948e-08, global = 1.095943e-08, cumulative = 3.937219e-09
ExecutionTime = 11.14 s ClockTime = 12 s

Courant Number mean: 27.73857 max: 38630.37
Time = 25.01

linear Wave piston position is 1.074151e-05
DICPCG: Solving for cellDisplacementx, Initial residual = 0.4571736, Final residual = 9.227115e-08, No Iterations 380
DICPCG: Solving for cellDisplacementy, Initial residual = 0, Final residual = 0, No Iterations 0
Execution time for mesh.update() = 1.28 s
time step continuity errors : sum local = 4.835948e-08, global = 1.095943e-08, cumulative = 1.489665e-08
DICPCG: Solving for pcorr, Initial residual = 1, Final residual = 9.711118e-08, No Iterations 156
DICPCG: Solving for pcorr, Initial residual = 1.439181e-08, Final residual = 1.439181e-08, No Iterations 0
time step continuity errors : sum local = 4.842107e-15, global = 3.515976e-16, cumulative = 1.489665e-08
MULES: Solving for gamma
Liquid phase volume fraction = 0.4999105 Min(gamma) = -49507.96 Max(gamma) = 51611.79
MULES: Solving for gamma
...

By the way, my case is a wave tank that generate stable linear wave, so after initial time, the run time information for every time step should looks likes no-change.

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