CFDEM®coupling - User Forum

Hi everyone!

I am new to CFDEM. Now, I try to use dump custom fx fy fz to output the resultant force of each particle. However, I am confused if the drag force from the fluid is already included in fx, fy and fz or not.

In addition, to record the contact force between the particle and wall, I use the 'dump wall/gran/local force'. I am also confused if the cohesion force from the cohesion contact model is included in 'dump wall/gran/local force'.

Could someone please help me solve these diffusions, as this is very important for me to continue my current work.

HI,

From the tutorials, the total of forceModel is output as f_dragforce for an atom and c_dragtotal for the entire particles.
I am wondering whether CFDEM can output the individual forceModel results per atom.

For example,

f_KochHillDrag, f_gradPForce, f_viscForce, and etc.

Best regards,

I recently completed the installation and compiling of CFDEM-Coupling and tried to run the packedBedTemp case provided in the tutorials. However, there was an error(something concerning mpirun and cfdemSolverPiso). As for the compilation, there were no issues with cfdemCompCFDEMsrc and cfdemCompCFDEMuti, but there persisted a missing operator error when I run cfdemCompCFDEMsol(although the log files suggest that the compilation was successful).

I have attached all the necessary log files.

Kindly request all of you to help me resolve this issue

Thanks in Advance

Hey
Can anyone tell me what is the maximum no. of particles I can stimulate in CFDEM in one time?
And also the minimum size of the model in which I can carryout my stimulation? Like what can be the minimum dimensions of a tube in which I can carry out my stimulation?

I am simulating particle transport in a rough fracture, and the rough fracture geometry and simulation screenshots are attached.

I simulated for both Newtonian fluid (fluid viscosity = 1cP, 10cP, 100cP) and non-Newtonian fluid (shear-thinning fluid).

In a lot of cases, I did not have the particle disappearing issue. But I am having the particle disappearing issue in some cases: (1) Newtonian fluid viscosity = 100cP and (2) Non-Newtonian fluid.

The total particle number in the simulation domain changing with time plot is attached.

Hello,
I am looking to do multiple commands during each of the coupling steps.
I was hopeful that i would be able to create an execute command that would
read another liggghts script and then continue the simulation, but was unable to do so.
I tried both include and jump.

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.