CFDEM®coupling - User Forum

Hello,

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]);

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!

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.

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.

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

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

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!

Dear All,
Hi,
I have a question about the value of timeStepFraction() that is returned by the line 136 in cfdemCloudIB.C and 218 in dataExchangeModel.C files. Can anybody explain me what value is showing this parameter? For your convenience, you can see its expression as follows:

scalar frac = ( (particleCloud_.mesh().time().timeIndex()-timeIndexOffset_)*particleCloud_.mesh().time().deltaT().value() - (couplingStep_-1) * couplingTime() ) / couplingTime();

When I use deltaT_CFD=2.5e-5s and deltaT_DEM=2.5e-7s, the case could run.
Part of the output info:

#cfd coupling
fix cfd all couple/cfd couple_every 100 mpi
nevery as specified in LIGGGHTS is overriden by calling external program (../cfd_datacoupling_mpi.cpp:77)
fix cfd2 all couple/cfd/force
restart ${restartstep} ../DEM/restart/liggghts_coupled.*
restart 800000 ../DEM/restart/liggghts_coupled.*