[smallgg]

Hello, CFDers.
Recently, I tried to simulate non-reactive fluidized bed using CFD-DEM by DPMFoam. I just use the the case of tutorial. However, something strange happens.
1、The predicted pressure drop fluctuate violently. Sometimes it will even show the negative pressure drop, which means the inlet pressure is lower than the outlet. Did anyone konw why?
I try to set the "relTol" to be 0 in "fvSolution" dictionary, but the innormal fluctuation is not disapper.
2、I use the command postProcess -func residuals to observe the residual curve. However the curve seems not convergence. I dont know why.(P.S.I cannot upload picture)
The version of OpenFOAM I used is OpenFOAM 8.0
Thanks a lot.