How to implement the EMMS drag model in MFiX?
There are some references to EMMS on the MFIX publications and citations page:
Hi, Charles
For the WEN-YU drag model, It seems the expression of drag coefficient coded in MFIX is different from that posted in the theory document, as shown below.
The multiplication by the solids fraction (EP_SM) is done outside this subroutine, where we also differentiate models A and B.
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Thank you for your information, Dr. Dietiker. But, there is still something confusing. EP_SM is not the main difference between Model A and Model B. Why it is was put outside the subroutine?
My guess is it was a arbitrary coding choice (pass the solids fraction as an argument to the subroutine or do the multiplication outside) made at the time the code was written.
Hi, Dr. Dietiker
Continue with the previous topic. For CFD-DEM OR MP-PIC simulation, in the code of user-defined drag model, should we divide the drag coefficient by the variable EP_SM in order to avoid adapting the original code? I found that for MFIX-DEM simulation, modification of drag coefficient for single particle has been coded in MFIX. Therefore, it is unnecessary to do that operation additionally, is it right? However, the variable V(i) in the modification seems redundant, because it does not appear in some momentum equations, such as MP-PIC momentum equation of parcel, as shown below. So, How should we code our DEM/PIC drag model correctly? Do we need to divide the drag coefficient by the variable V(i) in the code of drag model? I am confused about this point.
Hi，LiHeng
Have you compiled the EMMS drag model in MFiX?
I want to get some suggestions from you.