CFDEM®coupling - User Forum

Hi,
actually I try to set up a coupled cfdem case. I have a box with one moving wall. The wall velocity has to change with time, so I tried to use the ramp operation for this. Before I start the coupled simulation I fill the box with particles within 50000 timesteps. With constant wall moving everything works fine. My implementation of the ramp operation looks like the following:

Hi all,

I am looking to impose a certain coded source term to scalar fields (temperature and species) in my fluidisation model which is adapted from the ErgunTestMPI model. There are quite a bit of examples on how to do this on the internet and I have followed some of them, however, I haven't been able to get the model to work. I have a few questions which I hope the experienced users here can help me out:

Hi all,
I wanna implement the Lees-Edwards boundary condition (a mixture of periodic boundary condition and simple shear flow) on cfdemSolverIB. However, I didn't find anything on the papers regarding how it can be imposed on CFD and DEM separately. As we know, the position and velocity of fluid and particles should be updated every time step in Openfoam and DEM. The DEM (liggghts) part seems more tricky to me. Is there anyone who investigated this topic?
Thank you for your help.

I successfully coupled my case scenario (it runs without an error message). I believe I am missing something. Once post processing starts, I upload the DEM vtk file and the CFD vtk file. From paraview, I see that particle-fluid interaction occurs ONLY based on the initial DEM particle positions, BUT it seems as if the particles are fixed in place.

Does anyone have any suggestion or hints? What do you think I am missing? I uploaded my initial and run script. Thank you. It was based off of the ErguntestMPI.

Hello Friends, Greetings. Lets say we have a cuboid container defined by 6 primitive planes oriented along X-Y-Z axes, filled with spherical particles to a certain height, gravity acting along Z. When this system is fluidized (that is, particles are set into motion) or at rest,

1. How can we identify or group only those particles which are interacting with walls?

Thank you,
Jagan1Mohan

Hi all,

I try to write a element_exclusion_list to fix my mesh. I use the commend as follow:

fix cad1 all mesh/surface file /home/561/sl7844/scratch/Unresolved_CFDEM/BTM_600_1/DEM/BTM_600_coseholes_2.stl type 2 element_exclusion_list write ../DEM/list.txt scale 2.788 curvature_tolerant yes

After running this script, I got "ERROR: Fix mesh/surface (id cad1): 'write' mode for 'element_exclusion_list' only works in serial (../fix_mesh.cpp:177)
(../fix_mesh.cpp:177)"
But nothing is written.

Hello, I am Atsushi Onezawa. I work for chemical company and it is our first time to try to perform CAE analysis.
I would like to know computer spec enough to run CFDEM such as CPU, RAM size and Video card.
I am not familiar with computer because I am a chemist. I consulted an IT rep of my company and he requested me to research the computer spec suitable for CAE analysis. He intends to buy Dell Precision series workstation.
I would appreciate your input.

I have a run case which can be sucessfully run in my local computer and workstation. However, when the case was submitted to the super computer, the case can not start. And the log file gives following lines. Could anybody give me any suggestions? What's wrong with this? How can I fix it? Any suggestion is appreciative. Thanks!

I have a run case which can be sucessfully run in my local computer and workstation. However, when the case was submitted to the super computer, the case can not start. And the log file gives following lines. Could anybody give me any suggestions? What's wrong with this? How can I fix it? Any suggestion is appreciative. Thanks!

I am doing a simple simulation based on the ErgunTest tutorial using CFDEMSolverPiso, geometry and pathches are the same with the tutorial.

The fluid is pressure drive, with the outlet and inlet boundary for p: fixedValue p1 and p0 (p1>p0), for U: both zerogradient for outlet and inlet. The wall is no slip wall.

I supposed the pressure decrease from the inlet to the outlet in the runtime, however, strange pressure is found in the bed, some cells are large than p1, some cells are small than p0. I use GAMG with GaussSeidel smoother, the convergence of p is observed.