I was wondering if anyone has thought through or implemented variable coefficient of friction and restitution (COF and COR) for DEM particles in MFiX. In my application, I would like to relate the COF and COR for each particle to the physical properties and chemical composition of the particle. That would require declaring the COF and COR on the particle level. Currently MFiX implements a single, constant COR for particles within a phase and single, constant COF for all solids.
Hi Oluwafemi
As far as I know this has not been implemented in MFiX-DEM, but what you describe sounds pretty reasonable. It would involve changing some scalar variables into arrays so they can vary per-phase or per-particle, making sure the array is allocated and initialized, and making sure all references to these vars have the correct subscripts. The Fortran compiler should report a type mismatch if you miss any references.
Also, the MFIX GUI won’t know how to handle these, so you will have to either modify the GUI as well, or just manage these settings by editing the .mfx file - if you do that, there is a way to prevent the GUI from clobbering these settings (by using a custom .mfix file template).
If you decide to do this, let us know how it goes.
– Charles
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