Bounding epsilon error while running LRR/SSG using interFoam
Hello to every one,
I am trying to simulate supercritical multiphase flow (interFoam) using different RAS models to get the best solution. The simulation is running with k-e, RNG, k-wSST etc., but for LRR and SSG models, I am getting bounding epsilon message from the very beginning of the simulation. The epsilon blows up and the simulation stops after 1-2 seconds of simulation time. Further, in LRR, SSG Code:
div(((rho*nuEff)*dev2(T(grad(U))))) Gauss linear; was not accepted and Code:
ExecutionTime = 89.92 s ClockTime = 98 s Subhojit |
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Maybe a bug. To the other topic you mention. If you use the LLR turbulence model, are you under-relaxing the REqn? You can make it at least diagonal dominant by setting the matrix relaxation to 1 (same for epsilon). Same is valid for SSG. In addition, you did not provide any error message or other useful hints. fvSolution and the schemes you are using are of interest too. |
Many thanks for your valuable comment Tobi. I have used relaxation of 1 for the above-mentioned terms. The fvSolution and fvSchemes are:
Code:
ddtSchemes Code:
solvers // water channel, dam break tutorials Code:
ExecutionTime = 804.44 s ClockTime = 827 s Primary job terminated normally, but 1 process returned a non-zero exit code.. Per user-direction, the job has been aborted. ------------------------------------------------------- -------------------------------------------------------------------------- mpirun detected that one or more processes exited with non-zero status, thus causing the job to be terminated. The first process to do so was: Process name: [[21610,1],0] Exit code: 145 In ReynoldsStress.c file at line 243 Code:
- fvc::div(this->alpha_*rho*this->nu()*dev2(T(fvc::grad(U)))) Code:
const scalar minVsf = min(vsf).value(); Thanking you. Subhojit |
First of all, please clean your posts. Its just a mess. We have the code tag to include dictionaries, code and others in order to keep the format.
Probably your problem starts somewhere before: Code:
Courant Number mean: 1.97399e+30 max: 1.25118e+35 Anything went wrong here previously. Check out your states in paraview, e.g., at 1.70 s, 1,71 s 1,715 s to check where the problem starts and to analyze why your simulation crashes. As you can see, the Co Number kills everything. Probably somewhere is a high velocity (which can be limited by the fvOptions to make your simulation more stable). |
Thanks. I tried several fvSchemes to limit the alpha between 0 and 1, but still some -ve values are there which is possibly generating the -ve epsilon. The problem is starting with bounding epsilon and after some time getting a very high value of epsilon (both +ve and -ve).
Subhojit |
Bounding problems occur from time to time and therefore, we have the bounding functions that change the values to physical ones. The alpha field can have small negative values (this is a numerical topic) but I had such values in my calculations too. However, I never used the turbulence models you are using and hence, no idea what can cause the problem. In addition, we (the community) do not have insight into your case so well ... a bit tricky :)
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Subhojit |
For epsilon you don't need anything and definitely no source term ;). I guess you meant if you need some settings in fvOptions for epsilon. Well, the limitVelocity fvOptions will try to limit the velocity if you exceed the maximum number you specified. However, that does not mean that your simulation will run fine/correct/without errors. Its just a try to stabilize the simulation.
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What I noticed is that at most of the cells in the domain, the epsilon is close to the minimum value of 2.2e-16, and the calculated k (from R) is close to the minimum value of 3.3e-16. And at some cells close to the interface, the epsilon is increasing rapidly. The maximum velocity is below 10 m/s which is okay for my case. Subhojit |
I am not sure if the turbulence models you use are suitable for your case (VOF). No idea actually.
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Many thanks Tobi. Lets see how it goes.
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Hi, have you solved your problem? Recently, I meet the same problem,do you have some experience to share with me?
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