CFDEM®coupling - User Forum

Hi

I am getting strange behaviour of my simulations that seem to be very mesh dependent. Can anyone please give some insight? Sorry for the long post, but I have tried to give as much information as I can.

Hi,
I have a problem running some cases in parallel with cfdemSolverPiso. I distributed particles in a tube and run the case on 8 mesh partitions by a simple domain partitioning along the cylinder axis. The particles show an unphysical behavior when they pass the processor patch. They agglomerate before the processor patch. Any ideas what might be wrong in my case-setup? I run this case with the latest Liggghts version.
Thanks in advance.
Best regards
Ulrich

Hi

For my model I am using the cfdemSolverPiso solver (v2.3) with implicit momentum coupling. I see in the "couplingProperties" file, there is an option to limit the value of Ksl (momentum exchange field) that gets transferred ("implicitCoupleProps").

Limiting this value is supposed to give good stability in the solution. But is there any other reason for the limit? Should the value always be limited, or should the simulation be allowed to transfer the maximum value?

Thanks

Evan

Dear all

it took me a long time to find the error cause of the unit of the pressure. I thought p has the unit of kg/m/s^2, so i gave the dimension of the p in CFD [1 -1 -2 0 0 0 0]. But the unit of p in CFDEM from the tutorials is [0 2 -2 0 0 0 0], m^2/s^2, it means u^2. Am i right?
Could some one tell me why it is so? so in this case, the p in the CFD is not actually the pressure, but p/rho? or?

Thanks a lot!

best regards

Zhen

Hallo Christoph,

I was wondering, in order to generate a complex CFD geometry such as ship cull, propeller, is it possible to use unstructured instead of structured mesh in OpenFOAM while coulping with LIGGGHTS?

Thanks in advance.

David Long

When compiling any of the cfdem solvers (cfdemSolverIB, cfdemSolverPiso, cfdemSolverPisoScalar), I get this error:

Hi everyone,

I have installed the CFDEM, and I want to check whether it has been installed correctly. I typed cfdemTestTUT in my terminal, and it shows:

This routine will execute the CFDEMcoupling tutorial cases specified in tutorial-list.txt
Are the variables CFDEM_TUT_DIR=/home/kun/CFDEM/CFDEMcoupling-PUBLIC-2.1.x/tutorials
and CFDEM_SRC_DIR=/home/kun/CFDEM/CFDEMcoupling-PUBLIC-2.1.x/src/lagrangian/cfdemParticle correct? (y/n)

Then, I type y and Enter.

Another terminal is opened, and error happens:

--> FOAM FATAL ERROR:
No times selected

Hi, everyone,

According to the file of CFDEM coupling, after saving the ~/.bashrc, a new terminal should be opened. And in my new-opened terminal, it shows: make new dirs /home/kun/CFDEM/.../kun-PUBLIC-2.1.x? (y/n).

Is it the right steps? and when I choose y, it shows as follows:
mkdir: cannot create directory `kun-PUBLIC-2.1.x': Permission denied
bash: cd: kun-PUBLIC-2.1.x: No such file or directory
mkdir: cannot create directory `run': Permission denied
mkdir: cannot create directory `log': Permission denied

When I run twoSpheresGlowinskiMPI tutorial I got a error on a reconstructPar step:
=========
--> FOAM FATAL IO ERROR:
cannot find file

file: /home/sega/CFDEM/CFDEMcoupling-PUBLIC-2.1.x/tutorials/cfdemSolverIB/twoSpheresGlowinskiMPI/CFD/processor0/0.003/polyMesh/pointProcAddressing at line 0.

From function regIOobject::readStream()
in file db/regIOobject/regIOobjectRead.C at line 73.

FOAM exiting
=========

I use OpenFOAM 2.1.x, LIGGGHTS-1.5.1 and CFDEM-2.4.1

>> on behalf of Zhen Li

Dear all,

I just tried the new version of CFDEM Coupling. It worked very well. But I have a small problem by the post processing lpp.py. I copied the lpp folder according to the guide in the LIGGGHTS folder. If i tried to convert dump file to VTK, i got such an error:
Traceback (most recent call last):
File "/home/administrator/LIGGGHTS/mylpp/src/lpp.py", line 5, in
from dump import dump
File "/home/administrator/LIGGGHTS/mylpp/src/dump.py", line 194, in
import Numeric as np
ImportError: No module named Numeric