CFDEM®coupling - User Forum

Hello,

I actually try to extent a Liggghts simulation to a coupled simulation with CFD. In my Liggghts simulation I got a rotating disk, where the particles lay on. Furthermore I ve got a translating lid, which is adding a force onto the particles.

I now tried to add a fluid around the disk, so the particles run in this fluid. Now I face the problem, that the coupled simulation does not identify the moving STL-files I mentioned above.

Hi,

I am recently focusing on a particle cube system with a constant confining pressure, e.g. 50kPa. In my first code, I only use LIGGGHTS to exert this confining pressure and obtained the target pressure and void ratio. Then I write a restart file so that to restart the results in a CFDEM coupling procedure.

However, when I applied the restart file into a CFDEM procedure (the sample just be immersed in the hydrostatic water), I found the void ratio of my sample decrease sharply at a very instant time. I cannot figure out why this could happen.

Hi,
Please help me out.
I have installed VTK 8.1.0 version.

When I run cfdemSysTest and separately cfdemCompCFDEMall, following message coming.

$ cfdemSysTest

*********************************************
* C F D E M (R) c o u p l i n g *
* *
* by DCS Computing GmbH *
* www.dcs-computing.com *
*********************************************

Hello All,

I am running the ErgunTestMPI from the tutorial, and I want to plot the total head across the sample, and the differential head between specific layers. IS this possible in Paraview?

Thanks,
Nahid

Hello everyone,

I am running the coupled model with multi-sphere particles by creating a very loose packing density (%80 void fraction) inside a cylinder, where the air flows between the two ends of the cylinder.

I am using both friction and cohesion models in order to keep the particle as far as possible from each other to create such loose packing.

Each of my multi-sphere particle consists of one large particle in the middle and six particles with half large particle radius on the top of large particle (No overlaping).

Dear CFDEMers,

I am looking at the twoSpheres tutorial, do you know why a dummy rho field = 1 is created when the IBSolver is run? Can you simply define a new rho field if you want to simulate a different fluid? Will all the forces between particles and fluid be computed correctly?

Kind regards,
Frederiek

Hello,

I try to execute a coupled simulation with the cfdemSolverPIso. Unfortunately I always receive following error according to Ksl data, although I implented the Ksl in the "0"-folder:

timeStepFraction() = 0.02
LIGGGHTS could not find property Ksl requested by calling program. Check your model settings in LIGGGHTS.
ERROR: This error is fatal (../cfd_datacoupling.cpp:153)

What is meant with "check your model settings in LIGGGHTS"?
I really don't know how to fix this error, so every help is appreciated!

Thank you !

Kind regards

Hi, I'm simulating particles (~ 20000) moving in the fluid (with no initial flow).
After the calculation, I wanted to track the location of some particles (5~10 particles) in the simulation using paraview.
However, here is the problem that the 'id' of particle keeps changing with time variation.
(it means that if the 'id' of lowest positioned particle is No.490, after some time steps later the 'id' of same particle is not No.490)
The problem occurs due to the parallel processing?? or array style??

I am new to cfdem.I have tried varying all parameters in the packed bed tutorial and got different outputs.But when I vary the particle temperature in the liggghts_run file there is no change in the output, however high or low the value is.By default the value was 600 K and I have tried changing it to 1000K,500K,400K etc but everything gives me the same output for the fluid temperature distribution.

Hello everybody,

Some strange massage occurs when I try to run my simulation.
All 8 processor directories are available.
Maybe you know some advice.