CFDEM®coupling - User Forum

Hello everyone,

I am getting an unphysical pressure field for a few fluidized bed simulations. Everything else (velocity, voidage) seems fine. For most inlet gas velocities, simulations give expected value of pressure. However, for certain flowrate the values are erratic or even negative (possible but not expected) and are so throughout the bed. I am surprised with such fluctuating pressure field how is solution converging?

I am newer of CFDEM, there is a mistake when I run Tutorials. I always get this line:
rm: cannot remove '/home/administrator/CFDEM/administrator-PUBLIC-5.0/run/fillCylinder/CFD/0.*': No such file or directory

and that is the whole running process:
mesh was built before - using old mesh

// run_liggghts_fillCylinder_DEM //

/home/administrator/CFDEM/administrator-PUBLIC-5.0/run/fillCylinder/DEM

I am confused about the momentum coupling options in CFDEM viz implicit/explicit. Following are my questions.

1. what is TotalForceImp displayed in the cfdem log
is this done implicitly? sum(mesh.V()*Ksl.internalField()*(Us.internalField()-U.internalField()));

I ask this because of the next question.

2. On CFD side I have momCoupleModels selected as implicitCouple

While on DEM side for the resume file, I have: fix cfd2 all couple/cfd/force
How is the force calculated in this case? is it done explicitly?

i am newer of cfdem, there is a mistake when i run Tutorials,
it said no 0.* file, but there is a file after i see that folder, functions.sh is same
i don‘t know why

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.