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Weird Courant Number behavior with interFoam

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Old   August 24, 2014, 00:56
Default Weird Courant Number behavior with interFoam
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Praveen Srikanth
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Hello,

I am trying to initialize a particular volume of liquid inside a cylindrical capillary and let it settle to a stable topology because of the contact angle at the walls. I have two square inlets on the walls. I have set a maxCo of 0.5 but I see that the Courant number keeps jumping from around 0.2 to 0.8. I tried initializing the inital alpha.water field close to the final topology that I expect so that the velocities remain minimum but still these Co fluctuations occur. I am unable to figure out why these come up. I do have parasitic velocities at the interface which remain almost constant with time and my grid is pretty uniform so I do not see a reason for these fluctuations.

Any help is most appreciated. Thank you so much for reading. I am attaching the compressed case directory.
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File Type: gz c120_v4_00.tar.gz (10.2 KB, 2 views)
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Old   August 25, 2014, 13:43
Default An update
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Praveen Srikanth
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This is the behavior am talking about. Please give me some clues if you've any ideas. Stuck here for too long.

Code:
Courant Number mean: 0.00535526 max: 0.647063
Interface Courant Number mean: 0.00123651 max: 0.535682
deltaT = 1.14888e-05
Time = 0.482457

smoothSolver:  Solving for alpha.water, Initial residual = 1.60872e-05, Final residual = 4.9778e-09, No Iterations 1
Phase-1 volume fraction = 0.254528  Min(alpha1) = 0  Max(alpha1) = 1
MULES: Correcting alpha.water
MULES: Correcting alpha.water
Phase-1 volume fraction = 0.254528  Min(alpha1) = 0  Max(alpha1) = 1
smoothSolver:  Solving for alpha.water, Initial residual = 1.59992e-05, Final residual = 4.93622e-09, No Iterations 1
Phase-1 volume fraction = 0.254528  Min(alpha1) = 0  Max(alpha1) = 1
MULES: Correcting alpha.water
MULES: Correcting alpha.water
Phase-1 volume fraction = 0.254528  Min(alpha1) = 0  Max(alpha1) = 1
smoothSolver:  Solving for alpha.water, Initial residual = 1.59244e-05, Final residual = 4.88767e-09, No Iterations 1
Phase-1 volume fraction = 0.254528  Min(alpha1) = 0  Max(alpha1) = 1
MULES: Correcting alpha.water
MULES: Correcting alpha.water
Phase-1 volume fraction = 0.254528  Min(alpha1) = 0  Max(alpha1) = 1
smoothSolver:  Solving for alpha.water, Initial residual = 1.58593e-05, Final residual = 4.8365e-09, No Iterations 1
Phase-1 volume fraction = 0.254528  Min(alpha1) = 0  Max(alpha1) = 1
MULES: Correcting alpha.water
MULES: Correcting alpha.water
Phase-1 volume fraction = 0.254528  Min(alpha1) = 0  Max(alpha1) = 1
GAMG:  Solving for p_rgh, Initial residual = 0.0152028, Final residual = 9.46125e-05, No Iterations 2
GAMG:  Solving for p_rgh, Initial residual = 0.0012813, Final residual = 2.26789e-05, No Iterations 2
GAMG:  Solving for p_rgh, Initial residual = 0.000216587, Final residual = 6.85007e-06, No Iterations 2
GAMG:  Solving for p_rgh, Initial residual = 4.66816e-05, Final residual = 1.57006e-06, No Iterations 3
GAMG:  Solving for p_rgh, Initial residual = 1.11699e-05, Final residual = 3.16853e-07, No Iterations 3
GAMG:  Solving for p_rgh, Initial residual = 2.73222e-06, Final residual = 1.0629e-07, No Iterations 3
GAMG:  Solving for p_rgh, Initial residual = 7.38402e-07, Final residual = 4.92112e-08, No Iterations 2
GAMG:  Solving for p_rgh, Initial residual = 2.12433e-07, Final residual = 5.18073e-08, No Iterations 1
GAMG:  Solving for p_rgh, Initial residual = 8.1379e-08, Final residual = 8.1379e-08, No Iterations 0
time step continuity errors : sum local = 3.4878e-09, global = -1.6697e-10, cumulative = -4.09732e-06
GAMG:  Solving for p_rgh, Initial residual = 0.000800348, Final residual = 1.55905e-05, No Iterations 3
GAMG:  Solving for p_rgh, Initial residual = 0.000160921, Final residual = 6.48497e-06, No Iterations 2
GAMG:  Solving for p_rgh, Initial residual = 3.4046e-05, Final residual = 1.08616e-06, No Iterations 3
GAMG:  Solving for p_rgh, Initial residual = 8.44267e-06, Final residual = 3.90816e-07, No Iterations 2
GAMG:  Solving for p_rgh, Initial residual = 2.12454e-06, Final residual = 3.09364e-08, No Iterations 4
GAMG:  Solving for p_rgh, Initial residual = 5.7135e-07, Final residual = 3.73861e-08, No Iterations 2
GAMG:  Solving for p_rgh, Initial residual = 1.7608e-07, Final residual = 4.81433e-08, No Iterations 1
GAMG:  Solving for p_rgh, Initial residual = 7.62814e-08, Final residual = 7.62814e-08, No Iterations 0
GAMG:  Solving for p_rgh, Initial residual = 7.62814e-08, Final residual = 7.62814e-08, No Iterations 0
time step continuity errors : sum local = 3.26514e-09, global = -3.09067e-10, cumulative = -4.09763e-06
GAMG:  Solving for p_rgh, Initial residual = 0.000148746, Final residual = 5.9904e-06, No Iterations 2
GAMG:  Solving for p_rgh, Initial residual = 2.4146e-05, Final residual = 1.09183e-06, No Iterations 2
GAMG:  Solving for p_rgh, Initial residual = 5.17597e-06, Final residual = 2.3518e-07, No Iterations 3
GAMG:  Solving for p_rgh, Initial residual = 1.48494e-06, Final residual = 6.38681e-08, No Iterations 2
GAMG:  Solving for p_rgh, Initial residual = 3.67345e-07, Final residual = 9.42031e-08, No Iterations 1
GAMG:  Solving for p_rgh, Initial residual = 1.46331e-07, Final residual = 3.92244e-08, No Iterations 1
GAMG:  Solving for p_rgh, Initial residual = 6.4779e-08, Final residual = 6.4779e-08, No Iterations 0
GAMG:  Solving for p_rgh, Initial residual = 6.4779e-08, Final residual = 6.4779e-08, No Iterations 0
GAMGPCG:  Solving for p_rgh, Initial residual = 6.4779e-08, Final residual = 6.4779e-08, No Iterations 0
time step continuity errors : sum local = 2.77186e-09, global = -2.91414e-10, cumulative = -4.09792e-06
ExecutionTime = 480287 s  ClockTime = 482451 s

Courant Number mean: 0.00413568 max: 0.50113
Interface Courant Number mean: 0.000947386 max: 0.38948
deltaT = 1.14588e-05
Time = 0.482468

smoothSolver:  Solving for alpha.water, Initial residual = 1.53506e-05, Final residual = 4.28416e-09, No Iterations 1
Phase-1 volume fraction = 0.254528  Min(alpha1) = 0  Max(alpha1) = 1
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Old   October 17, 2014, 05:42
Default current status of problem...
  #3
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Arjun
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Dear praveen,
I am also experiencing a similar issue with my interFoam solver. can you update with the current status of the problem.
thanks
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