CFDEM®coupling - User Forum

Dear all,

Is it possible to control the life-time of particles in LIGGGHTS?

I want to simulate some solid-like droplets in the jet. Because of huge particle number, I think control the particle life time is an idea.

Thank you for any suggestions.

Best regards,
Zhaochen

Dear all:
I can run the tutorials,but when I want to see results,I find the results are separated in four folders:processor 0-processor 3. I tried to use the command "reconstructPar"to merge the results,Although it work with tutorial"cfdemSolverPiso-ErgunTestMPI" etc, this method did not work with the tutorial
"cfdemSolverIB". It warn
"
cannot find file
file: /home/zwt/CFDEM/CFDEMcoupling-PUBLIC-2.3.1/tutorials/cfdemSolverIB/twoSpheresGlowinskiMPI/CFD/processor0/0.03/polyMesh pointProcAddressing at line 0

Dear all,

Is it possible to deal with the case that particle size is smaller than the grid size? And how to separate the particle volume and drag force into small CFD cells? It is a problem that can nor be avoided when I want to control the Courant number in the local region with high velocity.

Goniva (2012) mentioned "so-called non-resolved approach presented here is applicable to those cases where particle sizes are smaller than the computational grid" . However, It seems that the case can run without errors when CFD cells are smaller than particle sizes.

Hi all,

Hi everyone,

A very simple question.

I am trying to implement buoyancy in my simulations and I started learning the fix buoyancy from the example in the command

fix bu all buoyancy level 0.06 dim z density 700

(http://www.cfdem.com/media/DEM/docu/fix_buoyancy.html)

Nevertheless, when I have it on I get this error

ERROR: Invalid fix style: "buoyancy"

any suggestion?

Cheers,
Luca

Hello everyone,

For my thesis, my supervisor would like me to calculate the overall coordination number (average of all coordination numbers per timestep) which should exclude the so-called "rattlers" (From C.Thorhton the average coordination number is defined as Zm = (2C - N1) / (N - N0 - N1), where N1 and N0 are the number of particles with only one or zero contacts respectively.

Does anyone have any suggestion, about how I could implement this in my code?

Greetings,
Luca

Hello everyone!

Dear all,
I used to running good, but when i changed the CFD/constant/polyMesh/blockMeshDict file, it comes out

[3] --> FOAM FATAL IO ERROR:
[3] cannot find file
[3] file: /home/tao/hui/CFDEM/erosion03122015/erosion/0.0138/validationcase/CFD/processor3/0/p at line 0.
[3] From function regIOobject::readStream()
[3] in file db/regIOobject/regIOobjectRead.C at line 73.
FOAM parallel run exiting

Hello,
can some one say me, which CFD mesh size is recommendable in dependence of the DEM particle size?

I have done it approximately and got 0.02*radius, if some one want to calculate the fluid stream between the particles.
But this mesh size causes quiet a big mesh.

Can some one help me?

Best regards
Robert

Hi all,

I am using liggghts from python. I am wondering if I could use the CFDEM coupling from python?

Best wishes,

Leo