CFDEM®coupling - User Forum

Hello Everyone,

I am a new user using the CFDEM. I am trying to use the heat transfer functions and have started with one of the tutorials (packedBedTemp). I can see that there are two main folders, DEM and CFD. In the DEM, there are also two input files: 1. in.liggghts_init and 2. in.liggghts_run. Besides, there are a few folders in the CFD folder, which I believe are the fluid properties. So, I have the following questions:

1. What is the difference between the files in the DEM folder? (the above 1 and 2 numbers).

Hello everybody,

Hallo,
I am simulating cfdem particle flow in a highly diluted fluid particle system. Particle sizes are in the range of 100µm, expected particle velocities on the scale of 100m/s. I have a question on the neighbor definition.
Currently I am using the following neighbor definition:
neighbor 1e-3 bin
When I decrease the value to 1e-4 it significantly slows down my simulation.
How can I estimate the proper choice for the neighbor definition?
Best
kalei

Hi all, I am trying to set up a simulation where particles are inserted in an extreme of a rectangular pipe. I have inserted them either with constant and gaussian velocity but when I visualize the results some of them start their motion with an extremely high velocity.

From the other hand I have been struggling trying to put a movile surface that compress the particles (along the z axis). So far, I have found that I should use servo command, but when I add to the DEM file the folowing instruction:

Dear all.
I would like to know if there is any way to create a restart file after a simulation has been stopped by using the post files of the DEM.
Thank you.

Dear All,

I have a couple of questions about the "processors command px py pz" (http://lammps.sandia.gov/doc/processors.html).
I am running a CFDEM simulation of a fluidized bed with HPC and I am trying to understand which could be the best set up for the processors.

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.