CFDEM®coupling - User Forum

Hello guys,

I want to simulate a small channel (11 micrometers) with small particles (2 micrometers).
Therefore I chose the "CGS" unit system. I tried to build a model with a 11 cm channel and 2 cm particles and it works fine.

But when I scale my region, neighbor, scaling coefficients, velocities, radiuses, blockMeshDict; it doesn't work anymore (Courant number rises very quick).

Dear all,

Recently I have read the code of virtual mass force, but there is a question that:

the original force = 0.5*rho_f*V_p*(Du/Dt-du_s/dt)=0.5*rho_f*V_p*(du/dt+u*div(u)-du_s/dt)

is that means in our virtual mass force model we use:

if splitUrelCalculation, using (Du/Dt) instead of (Du/Dt-du_s/dt),

if not splitUreCalculation, using (Ur-Urold)/dt instead of (Du/Dt-du_s/dt).

Is my understanding of this right?

Thank you!

Detian
2015.7.18

I think all went well installing LIGGGHTS along with CFDEM

so happy after more than 15 days day and night :)

the only problem is that I can't see the results (postprocessing) I don't have matlab
and octave seems to not work well to be called it show many errors
i some one could help little I can go faster

here what I get when running
tutorials/cfdemSolverPisoScalar/packedBedTemp

every thing went well

till here postprocessing i think

Hello,
I ran some examples from Palabos and LIGGGHTS and both softwares work fine separately. I followed all the instructions from https://github.com/ParticulateFlow/LBDEMcoupling-public. Unfortunetely I got some errors (see attached screenshot or text file). Does anyone know how to fix it? I am working on macosx 10.10.

Regards,
Mateusz

I got a problem when I'm trying to couple Palabos and LIGGGHTS as shown below.

scons: Building targets ...
mpicxx -o showcaseRectChannel -Wl,--whole-archive lmp_fedora -Wl,--no-whole-archive showcaseRectChannel.o /home/jian/Documents/LBDEMcoupling-public/src/liggghtsCouplingWrapper.o /home/jian/Documents/LBDEMcoupling-public/src/latticeDecomposition.o /home/jian/Documents/palabos/lib/libplb_mpi.a -L/home/jian/Documents/liggghts/src -llmp_fedora

Hello, I modified an example from the directory "tutorials", and it works well, but when I visualize the results with paraview, the results obtained with OpenFOAM have an scale time from 0 to 0,4 seg (just as I set in the inputs files), while the results in LIGGGHTS have an scale time from 0 to 40 seg (which is not what I set in the LIGGGHTS inputs). The results are consistent, the computations are made in the correct times, but the VTK's generated by lpp, don`t have the information of time.

Hello guys,

I try to simulate very small particles with diameters about 1 micrometer.
Therefore I want to change my unit system from "SI" to another system.

I looked at the "ErgunTestMPI_cgs" tutorial, but some things are unclear to me:
If I change the unit system in DEM folder (in.liggghts; units), the unit system in CFD will also change. - Is this right?
(Otherwise I cannot understand why "g" in CFD/constant/ is set to 981.)

HI all,

1. I read the paper of Di Felice (1994) and found the drag coefficient correlation had Re = dp*magUr/nuf as the definition of particle Reynolds number (without the voidfraction term), but found the voidfraction term was coded in DiFeliceDrag.C. Could someone clarify?

Original Code in .C file:
// calc particle Re Nr
Rep = ds/scaleDia_*voidfraction*magUr/(nuf+SMALL);

// calc fluid drag Coeff
Cd = sqr(0.63 + 4.8/sqrt(Rep));

Hey,

I want to register the position of simulated particles. I found the position file (CFD/timestep/lagranian/particleCloud) and their coordinates.
E.g. it looks like this:

CFDEM®coupling version 2.6.1 released (released March 3, 2014)
by DCS computing GmbH
+works with OF 2.2.x (latest release commit: 61b850bc107bdd60bbf1bf9a6417b9faf701d128)
+...
+bugfixes

Now I can only download this version from here: https://github.com/CFDEMproject/CFDEMcoupling-PUBLIC
This is for OpenFOAM2.3.x. For some reason I should stick to OpenFOAM2.2.x.

So I need CFDEM 2.6.1, but where can I download it?

Thanks,.