CFDEM®coupling - User Forum

Dear all,

I am simulating the heat transfer aiming to calculate the effective thermal conductivity of a sphere packing.

I started by modifying the example "cfdemSolverPisoScalar/packedBedTemp" and have the following questions.

1. Why are both in.liggghts_init and in.liggghts_run required in DEM folder?
ParDEMrun.sh calls "in.liggghts_init" but I got error if I delete in.liggghts_run.
Which file calls "in.liggghts_run"? and why is "run 0" defined in "in.liggghts_run"?

Hello All, the output file from a CFDEM simulation says that

"Reading voidfraction field voidfraction = (Vgas/Vparticle)".

Is it not that void fraction is Vgas/Vcomputationalcell?

Thank you,
Jagan Mohan.

I am using Liggghts-Public with cfdem coupling version 3.8 to simulate a triaxial test.

I saved the state of my first simulation with write_restart in order to reload it in another simulation

On loading the binary restart file into the new simulation, i got this error:
"Pair granular with shear history requires newton pair off"

I checked from the error section of the documentation the information i got was:
"This is a current restriction of the implementation of pair granular styles with history."

Hi everyone

I try to use dump custom fx fy fz f_dragforce(1) f_dragforce(2) f_dragforce(3) to record the total forces and fluid drag forces on each particle.

Hi everyone!

I am new to CFDEM. Now, I try to use dump custom fx fy fz to output the resultant force of each particle. However, I am confused if the drag force from the fluid is already included in fx, fy and fz or not.

In addition, to record the contact force between the particle and wall, I use the 'dump wall/gran/local force'. I am also confused if the cohesion force from the cohesion contact model is included in 'dump wall/gran/local force'.

Could someone please help me solve these diffusions, as this is very important for me to continue my current work.

HI,

From the tutorials, the total of forceModel is output as f_dragforce for an atom and c_dragtotal for the entire particles.
I am wondering whether CFDEM can output the individual forceModel results per atom.

For example,

f_KochHillDrag, f_gradPForce, f_viscForce, and etc.

Best regards,

I recently completed the installation and compiling of CFDEM-Coupling and tried to run the packedBedTemp case provided in the tutorials. However, there was an error(something concerning mpirun and cfdemSolverPiso). As for the compilation, there were no issues with cfdemCompCFDEMsrc and cfdemCompCFDEMuti, but there persisted a missing operator error when I run cfdemCompCFDEMsol(although the log files suggest that the compilation was successful).

I have attached all the necessary log files.

Kindly request all of you to help me resolve this issue

Thanks in Advance

Hey
Can anyone tell me what is the maximum no. of particles I can stimulate in CFDEM in one time?
And also the minimum size of the model in which I can carryout my stimulation? Like what can be the minimum dimensions of a tube in which I can carry out my stimulation?

I am simulating particle transport in a rough fracture, and the rough fracture geometry and simulation screenshots are attached.

I simulated for both Newtonian fluid (fluid viscosity = 1cP, 10cP, 100cP) and non-Newtonian fluid (shear-thinning fluid).

In a lot of cases, I did not have the particle disappearing issue. But I am having the particle disappearing issue in some cases: (1) Newtonian fluid viscosity = 100cP and (2) Non-Newtonian fluid.

The total particle number in the simulation domain changing with time plot is attached.

Hello,
I am looking to do multiple commands during each of the coupling steps.
I was hopeful that i would be able to create an execute command that would
read another liggghts script and then continue the simulation, but was unable to do so.
I tried both include and jump.