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 kilroy May 2, 2013 09:46

interDyMFoam "time step continuity errors"

Hello all,

I am having problems with my "waveDyMFoam" which I modified from "interDyMFoam". I am trying to run a simple 2D case where a box is floating on the water under the effect of waves. The video of the case can be seen here:

At first the case was not running because of some missing schemes in the "fvSchemes" file. So, I added the following lines under "divSchemes" section:

When I try to run the case, I get the following errors:

Quote:
 sixDoFRigidBodyMotion constraints converged in 1 iterations Constraint force: (0 0 0) Constraint moment: (0 0 0) Centre of mass: (10.3657 0.00896592 0.05) Linear velocity: (0.169457 0.0262615 3.6077e-17) Angular velocity: (-3.19807e-28 -1.37522e-26 -5.1003e-12) GAMG: Solving for cellDisplacementx, Initial residual = 0.000224045, Final residual = 8.12868e-06, No Iterations 2 GAMG: Solving for cellDisplacementy, Initial residual = 0.000224045, Final residual = 8.12868e-06, No Iterations 2 Execution time for mesh.update() = 0.23 s time step continuity errors : sum local = 5.05277e-05, global = -3.01844e-19, cumulative = -5.40294e-08 GAMG: Solving for pcorr, Initial residual = 1, Final residual = 8.97864e-08, No Iterations 17 GAMG: Solving for pcorr, Initial residual = 0.250457, Final residual = 5.28244e-08, No Iterations 15 time step continuity errors : sum local = 8.53279e-05, global = -1.02447e-11, cumulative = -5.40397e-08 MULES: Solving for alpha1 Phase-1 volume fraction = 0.666764 Min(alpha1) = -1.93586e-23 Max(alpha1) = 1 DILUPBiCG: Solving for Ux, Initial residual = 0.0130186, Final residual = 1.17418e-10, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 0.0946691, Final residual = 7.58036e-11, No Iterations 1 GAMG: Solving for p_rgh, Initial residual = 0.261841, Final residual = 5.56369e-08, No Iterations 12 GAMG: Solving for p_rgh, Initial residual = 0.000997295, Final residual = 4.38728e-08, No Iterations 7 time step continuity errors : sum local = 7.35319e-21, global = -4.08938e-21, cumulative = -5.40397e-08 GAMG: Solving for p_rgh, Initial residual = 0.000600283, Final residual = 5.20561e-08, No Iterations 6 GAMG: Solving for p_rgh, Initial residual = 0.00035003, Final residual = 4.53092e-08, No Iterations 5 time step continuity errors : sum local = 7.67551e-21, global = 6.55771e-21, cumulative = -5.40397e-08 GAMG: Solving for p_rgh, Initial residual = 0.000171914, Final residual = 7.8525e-08, No Iterations 4 GAMG: Solving for p_rgh, Initial residual = 5.06367e-05, Final residual = 6.19844e-09, No Iterations 6 time step continuity errors : sum local = 1.04979e-21, global = 1.00984e-21, cumulative = -5.40397e-08 ExecutionTime = 47953.3 s ClockTime = 48046 s Interface Courant Number mean: 2.38452e-06 max: 0.00400263 Courant Number mean: 0.000200405 max: 0.425284 deltaT = 2.62873e-13 --> FOAM Warning : From function Time::operator++() in file db/Time/Time.C at line 1029 Increased the timePrecision from 14 to 16 to distinguish between timeNames at time 12.8093 Time = 12.80933457039102 sixDoFRigidBodyMotion constraints converged in 1 iterations Constraint force: (0 0 0) Constraint moment: (0 0 0) Centre of mass: (10.3657 0.00896592 0.05) Linear velocity: (0.169262 0.026284 3.60775e-17) Angular velocity: (-3.19814e-28 -1.37523e-26 -5.10294e-12) GAMG: Solving for cellDisplacementx, Initial residual = 0.000221903, Final residual = 8.00376e-06, No Iterations 2 GAMG: Solving for cellDisplacementy, Initial residual = 0.000221903, Final residual = 8.00376e-06, No Iterations 2 Execution time for mesh.update() = 0.23 s time step continuity errors : sum local = 5.01594e-05, global = -1.26375e-19, cumulative = -5.40397e-08 GAMG: Solving for pcorr, Initial residual = 1, Final residual = 8.65576e-08, No Iterations 18 GAMG: Solving for pcorr, Initial residual = 0.181331, Final residual = 5.39143e-08, No Iterations 15 time step continuity errors : sum local = 7.78955e-05, global = -1.19518e-11, cumulative = -5.40516e-08 MULES: Solving for alpha1 Phase-1 volume fraction = 0.666764 Min(alpha1) = -1.88721e-23 Max(alpha1) = 1 DILUPBiCG: Solving for Ux, Initial residual = 0.0129951, Final residual = 6.3627e-11, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 0.0946374, Final residual = 9.16735e-11, No Iterations 1 GAMG: Solving for p_rgh, Initial residual = 0.205321, Final residual = 7.70156e-08, No Iterations 11 GAMG: Solving for p_rgh, Initial residual = 0.000734827, Final residual = 3.76525e-08, No Iterations 7 time step continuity errors : sum local = 3.98678e-21, global = -2.59775e-22, cumulative = -5.40516e-08 GAMG: Solving for p_rgh, Initial residual = 0.00041682, Final residual = 7.59192e-08, No Iterations 5 GAMG: Solving for p_rgh, Initial residual = 0.000186038, Final residual = 4.30575e-08, No Iterations 5 time step continuity errors : sum local = 4.24988e-21, global = -3.26612e-21, cumulative = -5.40516e-08 GAMG: Solving for p_rgh, Initial residual = 0.000101912, Final residual = 4.99173e-08, No Iterations 5 GAMG: Solving for p_rgh, Initial residual = 3.9727e-05, Final residual = 8.3358e-09, No Iterations 6 time step continuity errors : sum local = 8.22266e-22, global = -6.35014e-22, cumulative = -5.40516e-08 ExecutionTime = 47954.4 s ClockTime = 48047 s Interface Courant Number mean: 2.30322e-06 max: 0.0032262 Courant Number mean: 0.000207624 max: 0.544706 deltaT = 1.20649e-13 Time = 12.80933457039114 sixDoFRigidBodyMotion constraints converged in 1 iterations Constraint force: (0 0 0) Constraint moment: (0 0 0) Centre of mass: (10.3657 0.00896592 0.05) Linear velocity: (0.169412 0.0262994 3.60779e-17) Angular velocity: (-3.19822e-28 -1.37522e-26 -5.10071e-12) GAMG: Solving for cellDisplacementx, Initial residual = 0.00021926, Final residual = 7.84774e-06, No Iterations 2 GAMG: Solving for cellDisplacementy, Initial residual = 0.00021926, Final residual = 7.84774e-06, No Iterations 2 Execution time for mesh.update() = 0.23 s time step continuity errors : sum local = 3.57512e-05, global = 7.09289e-19, cumulative = -5.40516e-08 GAMG: Solving for pcorr, Initial residual = 1, Final residual = 7.51115e-08, No Iterations 20 GAMG: Solving for pcorr, Initial residual = 0.121942, Final residual = 9.90107e-08, No Iterations 14 time step continuity errors : sum local = 8.06169e-05, global = -3.4904e-11, cumulative = -5.40865e-08 #0 Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam220/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" #1 Foam::sigFpe::sigHandler(int) in "/opt/openfoam220/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" #2 in "/lib/x86_64-linux-gnu/libc.so.6" #3 void Foam::MULES::limiter(Foam::Field&, Foam::geometricOneField const&, Foam::GeometricField const&, Foam::GeometricField const&, Foam::GeometricField const&, Foam::zeroField const&, Foam::zeroField const&, double, double, int) in "/opt/openfoam220/platforms/linux64GccDPOpt/lib/libfiniteVolume.so" #4 void Foam::MULES::limit(Foam::geometricOneField const&, Foam::GeometricField const&, Foam::GeometricField const&, Foam::GeometricField&, Foam::zeroField const&, Foam::zeroField const&, double, double, int, bool) in "/opt/openfoam220/platforms/linux64GccDPOpt/lib/libfiniteVolume.so" #5 Foam::MULES::explicitSolve(Foam::GeometricField&, Foam::GeometricField const&, Foam::GeometricField&, double, double) in "/opt/openfoam220/platforms/linux64GccDPOpt/lib/libfiniteVolume.so" #6 in "/home/meta/OpenFOAM/root-2.2.0/platforms/linux64GccDPOpt/bin/waveDyMFoam" #7 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6" #8 in "/home/meta/OpenFOAM/root-2.2.0/platforms/linux64GccDPOpt/bin/waveDyMFoam" Floating point exception (core dumped)
And my analysis crashes around the 12th second. I checked my mesh and everything seemed ok to me.

Do you have any idea what may be the cause of that problem?

Thank you very much for your time and help.

Kilroy

 Tushar@cfd May 4, 2013 03:17

Quote:
 Originally Posted by kilroy (Post 424679) Hello all, I am having problems with my "waveDyMFoam" which I modified from "interDyMFoam". I am trying to run a simple 2D case where a box is floating on the water under the effect of waves. The video of the case can be seen here: https://www.youtube.com/watch?featur...&v=YKbj_7JMRl8 Also the case can be downloaded from here: https://sites.google.com/site/jordim...edirects=0&d=1 At first the case was not running because of some missing schemes in the "fvSchemes" file. So, I added the following lines under "divSchemes" section: div((muEff*dev(T(grad(U))))) Gauss linear; div((nuEff*dev(T(grad(U))))) Gauss linear; When I try to run the case, I get the following errors: And my analysis crashes around the 12th second. I checked my mesh and everything seemed ok to me. Do you have any idea what may be the cause of that problem? Thank you very much for your time and help. Kilroy

Hello,

Your deltaT is decreasing during each time step. For running transient solver you need to be extra careful with Co, deltaT.

I think the following link will be useful to you as you are working with problems related to interFoam solver:

http://www.cfd-online.com/Forums/ope...goes-1e14.html

:)

 kilroy May 6, 2013 09:44

Tushar,

Thank you very much for your time and help.

Right now I am running the simulation with fixed time step. Hope it will converge this time.

I will let you know.

Kilroy

 kilroy May 6, 2013 17:11

Running the simulation with fixed time step didn't help :(

I tried a time step size of 0.001 sec. but the simulation crashed even earlier than before this time. Now I am trying 0.0001 sec. but it is taking too much time.

Any other suggestions?

Kilroy

 Tushar@cfd May 7, 2013 01:39

Quote:
 Originally Posted by kilroy (Post 425655) Running the simulation with fixed time step didn't help :( I tried a time step size of 0.001 sec. but the simulation crashed even earlier than before this time. Now I am trying 0.0001 sec. but it is taking too much time. Any other suggestions? Kilroy

What is your max Co number ? try to reduce it to <1.
Also, set maxdeltaT value to be around <0.001, and try running the same.

As you are decreasing time step size, then it is obvious that it will take more time in computation.

:)

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