Hopper Example

Submitted by steve on Wed, 08/31/2011 - 13:50

I noticed that the coupling interval from the hopper tutorial has different numbers in the input file of LIGGGHTS (100) and in the couplingProperties from OpenFOAM (250). I guess that the numbers should be the same.

Further more I have seen that the parallelization is in different directions. I don't know if that is on purpose.
Can anyone tell me what the best way is to split for parallelization? In DEM best should be that all processors have same # of particles. Does it make sense to split the fluid domain in the same direction?

Thanks

Forums:

cgoniva's picture

cgoniva | Thu, 09/01/2011 - 08:13

Hi Steve,

concerning your first question:
giving the coupling interval in the in.liggghts_XY file does not have an effect when using MPI based coupling as LIGGGHTS is called ba the CFD code when it is time to couple. So it does not have an effect.

concerning your second question:
you are right that DEM works best if #particles is well distributed over the procs. For CFD the load should also be well distributed. For pure CFD this means same #cells for every proc and a small proc-proc interface. As a large amount of CFD-DEM work is the coupling it might be a good idea to have the same decomposition for DEM and CFD.
Nevertheles the coupling is written in a way to allow different decompositions on DEM and CFD side which is important when the CFD domain is much larger than the DEM domain.

Hope that I could give you some useful hints...

Cheers,
Chris