Error indication in 3D DEM simulation,DT<DT_MIN

MFiX
#1

Dear all，
When I use SMP production solver on Linux system. Error indication occurred while running 3d DEM simulation: DT<DT_MIN. I modified the grid and time step, but the same problem still appeared. I am looking for the answer in the forum, but still can not solve, please help to solve.
Thanks!
28and8r_2022-03-30T203822.770911.zip (36.2 KB)
28and8r.mfx (13.8 KB)

#2

Does it run in serial? DMP?

DT<DT_MIN means the simulation is not converging, which could be a number of things.

#3

Please see 8.4. Frequently Asked Questions — MFiX 22.1 documentation

#4

This is SMP. What are the main causes of this in general?

#5

Please see 8.4. Frequently Asked Questions — MFiX 22.1 documentation

#6

I tried to follow the instructions to change the Settings, but it still didn’t work.

#7

What did you try exactly? I can get it to run by switching to ideal gas law. You did not include the particle_input.dat file though so I started with an empty bed.

Often a better convergence is achieved with ideal gas law than with constant gas density. If poor convergence or failure to converge is observed while using constant gas density, it is recommended to switch to ideal gas law. In this case the average molecular weight or individual gas species molecular weights must be defined, and gas pressure and temperature must be defined in all initial and boundary condition regions.

2 Likes