[dussa]

Hi everyone,

I'm having a bit of trouble figuring out how to control the lagrangian particle substep size in a eularian-lagrangian simulation. The timestep is set for the eularian phase in the controlDict, say 5e-4. If I would like the step size for the lagrangian phase to be 5e-5 is this set in the constant/kinematicCloudProperties at the points shown in bold:

pairCollisionCoeffs
{

pairModel pairSpringSliderDashpot;
pairSpringSliderDashpotCoeffs
{

useEquivalentSize no;
alpha 0.02;
b 1.5;
mu 0.10;
cohesionEnergyDensity 0;
collisionResolutionSteps 100;

};

wallModel wallSpringSliderDashpot;
wallSpringSliderDashpotCoeffs
{

useEquivalentSize no;
collisionResolutionSteps 100;
youngsModulus 1e4;
poissonsRatio 0.23;
alpha 0.01;
b 1.5;
mu 0.09;
cohesionEnergyDensity 0;

};

};



I am suspicious this is not where you specify the lagrangian substeps as they are prescribed twice (once for particle-particle, and once for particle-wall interactions). If anyone has any insights as to if this is correct or not, or where the correct place to specify substep size is, please let me know,

Regards,
Rob

[dussa]

So I've had a bit more looking around and it seems others have had the same question in the past, with one post reporting it as a bug that it was not available to be set: https://bugs.openfoam.org/view.php?id=953

and another post saying that in OpenFOAM-2.0 that automatic time sub-cycling to guarantee stability was added: http://www.openfoam.com/releases/ope...lagrangian.php

I also found another thread where someone was attempting to run DPMFoam and posted a portion of their output (DPMFoam case worked perfectly in the first run but crashes in every subsequent run!!), where it shows that there is something called "move-collide subCycle" when the kinematicCloud is being evolved. I think this might be what I want to change for my simulation, however I still can't figure out where this is done. If anyone has any ideas pleasse let me know.

Rob

[Shah Akib Sarwar]

Were you able to figure this out?