CFDEM®coupling - User Forum

Hi,
Is there anyone knowing how to set the environment variables? I tried to paste the lines at the beginning, middle and last of the "bashrc.file" . However, when I run "$CFDEM_PROJECT_DIR", "$CFDEM_SRC_DIR" and "$CFDEM_LIGGGHTS_SRC_DIR", it has no results shown the variables are not set correctly. Do anyone know how to modify it? Thank you.

Hi,

In my coupled simulation particles that contact with the walls escape from the domain after few collisions with the walls. I need the particles to stick to the walls as they hit the wall and stay there, and any particles that collide with them also to stick to them near the wall. I would appreciate if you can help me where to add this in the code. I was thinking of zeroing the COR. I appreciate any advise?

Regards,
Vajiheh

Hello all,

I am getting considerable difference in results between resolved CFDEM and resolved with dynamic mesh refinement. My case as shown in is particles flowing through a slot/constriction. The number of particles left in the domain is plotted against time for the two methods in . Both the simulations are identical (with same random seed and initial position of particles) except that one is resolved with static mesh and the other is resolved with dynamic mesh.

Hi, I try to compile the lastest cfdem according to the githubAccess_public.pdf
It all goes fine until I reach the step:cfdemCompCFDEM
The cfdemSolverPiso has the error and I have searched the forum but still donot know why , could somebody help me ,thanks

// log_compileCFDEMcoupling_cfdemSolverPiso_cfdemSolverPiso-2013-01-09-23:26 //

/home/chenxizh/CFDEM/CFDEMcoupling-PUBLIC-2.1.0/applications/solvers/cfdemSolverPiso

Hello:

Thank you for your previous answers. I'm beginner in cfdem and i'm runnig tha basic examples. One of my previuous questions was about the couplinginterval. For deciding the suitable timestep, I have to decide the DEM timestep fisrt and later depending on the couplig interval to decide a time step for cfd so that time step for cfd = time step for dem x coupling interval. Therefore, for high values of couplinginterval we have a weak coupling and for low values a strong coupling.

Hello all,

I am trying to grow particles in a certain region upto a certain size in liggghts with CFDEM coupling. I want to try this because inserting particles as a stream with their final diameter seems to cause spikes in the CFD calculations.

I can do this easily with only liggghts. However in CFDEM, I am having the problem of reassigning the group everytime new particles are inserted in the region or stop growing once the particles have reached their final diameter.

group new_insert region insert

My IE explorer cannot display the whole captcha image, I cannot reply, so I create a new topic. The following files are the log file and the in.meshGran file. During the cfdemcoupling, the atoms number became 0. But it works fine in the liggghts.

I tried to use the insert/steam or insert/pack command to make the particle inject into the reactor by a certain velocity continuously, so I write these commands in the in.XXX file:

Hi,

I'm beginner in CFDEM. I've runned SttlingTestMPI tutorial and dranw the numerical and analytical velocities using the routine in octave. The results seem ok but when the particle reaches the terminal velocity, the velocity slightly oscilates. I think the oscilations are caused by the transition of the particle from one cell to the other. Theoretically, as shown by the analytical results the velocity should be constant. Is there any possibility to improve the numerical results to reach a constant velocity?. I add the file generated by Octave in eps.

Hi,

I have encountered a problem when running fillCylinder in tutorials: cannot pour particles

I use the following syntax:
fix ins nve_group pour 10000 1 200 region bc vol 0.4 100 diam 0.001 0.001 dens 200 200 vel 0. 0. 0. 0. 0.
Then an error comes:
ERROR: Invalid fix style (modify.cpp:710)

The DEM input file and the log file for the run are attached.

Could you please help me solve this problem?
Thanks.