CFDEM®coupling - User Forum

Hi,
I've got a little issue with compilation on a new cluster (after everything has been running well with the old Uni cluster I was using, that is being decommissioned next month). I have compiled LIGGGHTS manually as a shared library, and it has created the liblmp_mpi.so in the LIGGGHTS /src directory, and i have the liggghts executable lmp_mpi. I compiled without VTK.

Hallo everybody.

I have a question about the rotation of cohesive particles when using CFDEM coupling. The particles start to rotate when they overlap with another particle or a wall. If I'm not using CFDEM coupling (only DEM), they don't rotate (see rotate.png). I don't use any rolling friction model. Can someone explain me this behaviour?

many thanks in advance.

Johannes

Dear all,

I am wondering whether we have a method about monitoring the permeability of the particles specimen. As far as I know, we can monitor the quantity of flow in the outlet boundary to calculate the permeability of the specimen manually. However, I haven't found a command about outputing the quantity of outflow. Could someone tell me which command should I use? or is there any possibility that we output the permeability of the specimen directly?

Thanks you very much!
Regards,
Rachel

Hi everyone,

Is the premium two-fluid CFDEM-Coupling meant ot be used only for fluid-gas-particles, or is it also possible to simulate two immiscible fluids in a fluid-fluid-particle simulation?

Cheers,
A

Dear all,

When I applied cfdemPisoSolver in my simulation, I found there is no interaction between stl mesh wall in liggghts part and water in openFoam part. Now, I am wondering whether there exist a method to define the contact betwwen water and walls?

In other words, if I want to simulation a similar problem about the drop process of a container full of water, how to define the interaction between water and the container? Is there any method? Any suggersions or clues are appreciated!

Best regards,
Rachel

Hi,
Is there any way to calculate and output the total particle/wall heat flux due to the conduction through contacts areas and conduction/convection through the gas?

Thanks

Simone

Dear all,

I want to ask a question. As I see in this forum, the mesh size of OpenFOAM should be 3-4 times of the particles diameter. If I have some kinds of particles with different diameters such as 1mm, 0.5mm, 0.1mm. Should my mesh size be 3-4 times of the diameters of the larger particles or the smaller particles? Thank you very much.

Besr regards,
Rachel

Dear all,

Dear all,

I am using Model A with following code lines, where implicit method is used. For the fluid force on a particle (Fpf), there are mainly three kinds of components, fd, f_pg (pressure gradient force), f_v (viscous force).

1) what is the true meaning of f_dragforce, does it only referee to the pressure gradient force f_pg + viscous force f_v, namely (Fpf-fd) ?

2) If f_cfd2 is the sum of Fpf for all particles, why I find f_cfd2 < sum (f_dragfroce) << pressure drop * area? The case with cylindrical bed is used.

Hi everyone,

I am simulating the pressure drop caused by a compressed bed of packed particles. On the DEM-side I mechanically compressed particles with a moving mesh. I then used this state to create the restart data where I changed the STL for a wall. On the CFDEM-side I apply a velocity of 0.001 in the inlet. I am using cfdemSolverPiso.