Hello!
I am trying to simulate a shear flow where a wall made of particles shear a granular body while being completely submerged in fluid (via CFDEM). To bypass the use of servo walls, I just set the total weight of the particle wall to be several times the flowing body. I use Archimedes+DiFelice for my fluid forces. I set the fluid forces to act only on the flowing particle body so that the bouyant forces will not affect my particle wall in such a way that I can keep the weight of the said wall constant even if I change my fluid densities.
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fix cfd flowing_particles couple/cfd couple_every 10 mpi
fix cfd2 flowing_particles couple/cfd/force/implicit
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However, I find that relative to pure LIGGGHTS simulations, the total pressure within the flowing body decreases and I find that fluid forces are still being calculated for the particle wall (and particle base which is not even moving). How can I apply fluid forces exclusively for a specific group and have it zero for the others? Or is there a better way to achieve the system I described above?
Thanks in advance
kfcui