CFDEM®coupling - User Forum

Dear all,

When I use the CFD package in the coupling simulation, in the initial conditions of velocity, i.e. CFD-0-U, I found all the three velocity of fluid must be set in three direction (x,y,z). However, when I have a circular boundary condition, the initial velocity of fluid should be always in the radial direction. This cannot be realized just using that in x, y and z directions. My question is: is there any possibility that we exert the radial velocity boundary conditions for a circular fluid boundary? Many thanks.

Regards,
Rachel

Dear all,

I am now focusing on simulating the process of fluid injection into dry sand (DEM particles). As I know, for the fluid field, I have to determine some certain boundary conditions for all fixed fluid boundaries. However, if I want to simulate the infiltration process, such as water infiltrate into dry sand, is there any method that I simulate the gradual infiltration process of the sand sample? Could anyone please give me any clues? Thanks very much.

Best,
Zheng

Dear All,

I am trying to run a CFDEM simulation (similar to the Ergun Test Case) on a HPC cluster with 200 to 4000 cores.
For less than 50 cores (I used 18 cores and 48 cores) everything works perfectly, but increasing the number of cores up to 200 I get an error from OpenFOAM:

[0] --> FOAM FATAL ERROR:
[0]
cfdemCloud:: local mesh has zero cells. Please check the mesh and the decomposition!

Is there a way through which we can create atoms using the create_atoms command after every n timesteps in a region? I know that, it could be done by following commands for spherical particles.

Dear All,

I am trying to run a modified Ergun test case, therefore a CFDEM fluidized bed simulation, on a HPC cluster. As "modified" Ergun test case, I mean (i) more and smaller particles in a (ii) bigger cylinder (actually a geometry consisting of a cylinder on top of a truncated cone).

Do you know which is the best configuration/set up to run efficiently such a CFDEM simulation on a HPC with up to 4000 cores ?
Any trick ? Any hint to have a good HPC scalability ?

Dear All,

Hi all I am installing CFDEM on a cluster, and I am having some issues. I followed the instructions on the documentation and I succeed installing OpenFOAM and LIGGGHTS. To install LIGGGHTS I had to to tweak the Makefile.auto to download the vtk lib ( USE_VTK ?= "OFF" and AUTOINSTALL_VTK ?= "ON").

Just in case I am using the step by step installation
cfdemCompLIG
cfdemCompCFDEMsrc
cfdemCompCFDEMsol
cfdemCompCFDEMuti

Hi all, I am running a simulation based on the periodic channel tutorial. I succeed running several variations of It but now suddenly the simulation crash always in the same point. As you can see in the attached log file below, it's not due to high Courant number or problems converging the pressure field. Any idea?

Hi!

I made a bash script that converts dump files to VTK. I tested it on several cases and it's two times faster than LPP. Check it out here https://github.com/alek-/dumpToVTK

Works only for "id type x y z ix iy iz vx vy vz fx fy fz " dump, but it's easy to modify.

Cheers

Hello, I am using the periodic channel tutorial. I want to modify the fluid velocity to make it time depending. In the fvOption file, I need to adjust it to set that the flow velocity starts to act after a specific time. Currently, the flow has a velocity at time = 0 s. I want to fix another start time, for example at t = 1 s. I appreciate any suggestions.