CFDEM®coupling - User Forum

This is a forum dedicated to CFDEM®coupling using the LIGGGHTS® DEM code and OpenSource CFD.

Need Help for Initialization

Submitted by ali_km on Wed, 04/29/2020 - 01:21

Dear Friends
I'm trying to understand how to setup my case. I'm working with cfdemSolverPisoScalar solver and I have reviewed the initialization files "in.liggghts_init" & "in.liggghts_run".
In my understanding "in.liggghts_init" initialize DEM solver and "in.liggghts_run" do the coupling with CFD solver, however, some of the data in these files doesn't match.

Not enough processor slots to run the simulation

Submitted by napattorn1 on Wed, 04/22/2020 - 13:49

Greeting,

I am very new to CFDEM and OpenFOAM in general and just about looking to simulate a fluidized bed combustor.

I looked around in this forum and found that ErgunTestMPI is a fluidised bed, so i wanted to run this file and start modifying it to fit my model. However, I promptly ran into the following problem as I attempted to run the simulation:

Archimedes or ArchimedesIB forces problem

Submitted by mofazli on Fri, 04/17/2020 - 04:14

Hi everybody,
I am working with ArchimedesIb force in cfdemSolverIB, however, it seems that the code is giving me the wrong value. As you can see in the ArchiumedesIB.C and ArchimedesIB::setForce() (Line 113), the buoyancy force is calculating by
force += -g_.value()*forceSubM(0).rhoField()[cellI]*particleCloud_.mesh().V()[cellI]*(1-voidfractions_[cellI]);

PorousBaffle in OpenFoam

Submitted by sashagertrude on Thu, 04/09/2020 - 03:07

Hello,

I would like to simulate a filter that retains most of the particles while allowing water to pass through. I created a case in OpenFoam and it works fine using a porous baffle for the filter. Now I wanted to know how LIGGGHTS will interact with a porous baffle (porousBafflePressureFvPatchField). Is there a boundary condition that I should be focusing on to simulate the scenario mentioned above? Or if anyone can direct me to sources that would be awesome.

Thank you!

mpirun error

Submitted by ali_km on Tue, 04/07/2020 - 02:48

Dear folks
I'm new to CFDEM and I'm trying to run a tutorial example of following:
"tutorials/ParScale/cfdemSolverPisoSTM/packedBedTempParScale"
however, after I type "./Allrun.sh" this error shows up:
--------------------------------------------------------------------------
mpirun has detected an attempt to run as root.
Running at root is *strongly* discouraged as any mistake (e.g., in
defining TMPDIR) or bug can result in catastrophic damage to the OS
file system, leaving your system in an unusable state.

Elastic Walls

Submitted by llee0311 on Fri, 04/03/2020 - 20:11

Hello there!

My goal is to simulate particle plugging effect in a channel.

What has been achieved so far:
The fluid flow domain is a long trapezoidal or a wedge shaped box (figure attached).
The BCs are no-slip walls, constant inlet velocity, and constant outlet pressure.
A snapshot of one of the particles plugging results is attached, and you can see the particle accumulation.

Different number of core for CFD and DEM in parallel running

furkhat's picture
Submitted by furkhat on Thu, 04/02/2020 - 08:20

Dear all,

I'm running the EngunMPI tutorial case on HPC using 40 cores and I detect that the number of cores for DEM and CFD parts the same, but in is not good becouse CFD parts is very sensetive for number of cores. In this situation I wanted to run DEM using 40 cores and CFD -5 cores. Is it possible to run CFDEM in this way?

Best regards, Furkhat

Different number of core for CFD and DEM in parallel running

furkhat's picture
Submitted by furkhat on Thu, 04/02/2020 - 08:19

Dear all,

I'm running the EngunMPI tutorial case on HPC using 40 cores and I detect that the number of cores for DEM and CFD parts the same, but in is not good becouse CFD parts is very sensetive for number of cores. In this situation I wanted to run DEM using 40 cores and CFD -5 cores. Is it possible to run CFDEM in this way?

Best regards, Furkhat

Implementation of a viscosity model dependent on solid fraction of fluid cell

Submitted by Nathan_yin on Tue, 03/31/2020 - 15:50

Hi, I am simulating a shearing test(Rheology test) of particle suspension. As it is well known that the viscosity of fluid is closely related to the solid fraction of the particles in a particle suspension system. So I was wondering if I want to consider this effect and use variable viscosity dependent on the solid fraction of the fluid cell, which part of the source code I should modify.

Thank you!

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