CFDEM®coupling - User Forum

Hi all,
I've just started using Ubuntu, and I'm finding it difficult to follow the procedure for installing liggghts, can anyone please guide me through the procedure involved in the installation of liggghts?
Thank you.

Hi all,

I am using unresolved CFDEM method with pisoFoam solver for a simulation containing a porosity (cellZones, DarcyForchheimer). For the wall of the porosity I am using hertz contact model and the colloid package included by wall/region command.

During simulation when the first particle (pair_style: hertz) reaches the wall of the porosity I get an error and I can't figure out why. Maybe someone could give me a hint.

ERROR on proc 1: Internal error (../tri_mesh_I.h:109)

Thanks and regards, Laura

Hi all,

Regarding the CFDEM program, I've studied the governing equations behind the unresolved vs. resolved CFD-DEM.

As we're all aware, the unresolved CFD-DEM method is applicable only if the DEM particle size is significantly smaller than the CFD cell size.

However, I was wondering...could we use the unresolved CFD-DEM if the DEM particle size is significantly larger than the CFD cell size?? Will that cause any convergence issues ? Will that affect the accuracy of the results? Can we get the same realistic results ?

Hello everyone,

I am simulating a simple case of particle flow in horizontal pipe with fluid as continuum phase. Now considering two cases:

Case 1: Fluid density = 100 kg/m3
Case 2: Fluid density = 900 kg/m3

All other parameters are same in both the cases. I am able to run the Case 1; but while running Case 2, particles are disappearing from the pipe after a certain distance from the inlet factory (as shown in the Case2.gif).

Is it possible to simulate pure scalar transport with cfdemSolverPisoSTM (i.e. species transport without heat transport).

The tutorials only feature combined heat and species transport.

Hi I'm running the twoSpheresGlowinski, everithing is OK but I i'm not able to reconstruct the case, I get the following error message.

####################################################################################################################################################################################################################################
Reconstructing fields for mesh region0

Time = 0.003

--> FOAM FATAL IO ERROR:
cannot find file

Hi,

I am a new user of CFDEM. I use Linux Mint 17.3. To install CFDEM, I first installed OpenFOAM as recommended using git, and then followed to install LIGGGHTS and CFDEM. However, some errors show up as below when I complied CFDEM. Apparently, it seems "CFDEM/CFDEMcoupling-PUBLIC-dev/src/lagrangian/cfdemParticle/etc/additionalLibs_dev" does not exist. But what I have in that directory is
additionalLibs_2.4.x
additionalLibs_3.0.x
additionalLibs_3.2

Hi, All:

I am a bit confused about the Equations used to calculate the drag force term in GidaspowDrag.C:

https://github.com/CFDEMproject/CFDEMcoupling-PUBLIC/blob/master/src/lag...

in line 195:

Ufluid = U_[cellI];

Is this the superficial velocity (U_superficial = U_real*voidfraction) or the real fluid velocity? From my understanding it is real velocity, is that correct?

I have inserted particles with young's modulus 1e5 into a cylindrical container and obtained the wall stress. Actual young's modulus of the particle is 1.2 e11. Since I was not able to insert particles with this youngs modulus I intensionally reduced young's modulus and hence im getting reduced wall stress. Is there any factor to be multiplied with the obtained stress to get the actual stress? What is the correlation between these two parameters?
Thanking you

Ullas

Hi,

I am new to cfdem and I am going through the tutorials. There are two separate folders, one for cfdemSolverPisoScalar and cfdemSolverPisoSTM. Both of them have similar case - packedBedTemp. The shell script files for both the tutorials are also similar, except for the solver used. In fact, they both give similar results. So, I'd like to know what is the different between these two solvers and how to know, which one to use for a specific case.

Thank You,
Yesaswi