I input 2000 particles, but there are 3600 particles in the system

MFiX
#1

Hi there,
Recently, I have been working on MFIX-DEM model. In my work, there is a small rotating drum, like this:
image
I used ‘particle_input.dat’ file to input 2000 particles, however, it turns out that MAX_PIP is equal to 3600. (there are 5 layers of my particles and each layer has 400 particles. Thus it seems like two layers in each side are doubled, 2000+800*2=3600). When I changed ‘cyclic_z=.T.’ to 'cyclic_z=.F. ', MAX_PIP will be 2000. Is there any keywords I missed when I used a cyclic boundary condition? Or any ideas for me to understand 3600 particles? Any suggestions will be very grateful.

#2

Copies of particles near cyclic boundary are created to account for collisions across the boundary. This is why you see 2000 particles when the boundary is a solid wall (cyclic_z=.false.) and 3600 when the boundary is cyclic (cyclic_z = .true.). This is the same logic the code uses for MPI.

#3

Thank you very much, Jmusser. You really helped me.:slightly_smiling_face: