CFDEM®coupling - User Forum

Hi,

I'm new here and would like to ask two things that I need for my project. I would like to be sure if this is possible using this software.

- If I have for example water falling in a box, can I get the forces and torques acting on this body (the mesh) due to the fluid?
- May I change the states of the body (position, velocity, orientation, angular velocity) based on the forces and torques?

Thanks in advance for the help! Danmiela

Hi there,

I installed CFDEM based on OF 1.7.x and liggghts 1.3.3. (Remark: other than issues with using consistent compilers and the -fPIC option and fiddling around with paths it went smooth) and try to run it on cfdemSolverPisoCase_shared/settlingTestMPI

The error occurs in the bash function parCFDDEMRun(). It executes decomposePar successfully, fails removing couplingFiles/* because there are none. The fatal error occurs during the execution of the solver. Please find the complete error message below.

Hi Chris,

maybe you realise that I am trying to get a bit deeper into the code. And for the drag law I have some questions:

1) For the calculation of beta (I think it is mostly called this way) you used the term alpha^(1-xi). In different publications I found three different exponents: -xi, 1 - xi and 2 - xi
I haven't received the original paper, yet, so I don't know which is the correct one.

Hi everyone,

I've got some questions about the coupling.

1. If a density field is provided, the drag force is calculated in the correct way. What about the KSL-values? I haven't found anything about the density in the code and if I look at some references about KSL the equations to calculate it seems to be different. So maybe anyone can give me a hint where to find a description about the used KSL model (I think in a further version the Gidaspow-model was mentioned?).

2. Furthermore, is there any other reason than stability for the limitation of the KSL-value?

Dear all,

there have been some issues with compiling cfdem with version 2.0.0 and 2.0.x.

It was tested and worked with 2.0.x.

With 2.0.0 errors ( MPI::Win::Free() ) might occur.

Please use the version 2.0.x and not the pre-compiled versions.

I'll do another testing and let you know as soon as everything has compiled fine.

Cheers,
Chris

Hi All,
I am looking for some directions about how to increase the
number of particles in the tutorials and how to setup a
case for running with 16 physical computer nodes.
Any clue is very welcome.
Thanks,
Alex
P.S. Is there a old case with liquid fluidized bed using "file coupling" ?

Hi,
When I run coupled cfd-dem simulation, there is some problem importing the stl file.
---------------------
Importing STL file 'geotest.STL'
ERROR on proc 0: Cannot open stl file geotest.STL.
----------------------

But when I run liggghts only, there is not any problem. I found from previous post that I should try absolute path. May I know how does it work? I tried :
fix cad all mesh/gran $Absolute_path/ geotest.STL 1 1.0 0.0 0.0 0.0 0.0 0.0 0.0
then there is error message:
ERROR on proc 0: Substitution for illegal variable

Thanks!

Hi,

I successfully compiled cfdemParticle, but when I compile the solver, I got an error like this:

/usr/bin/ld cannot find -llangrangianCFDEM

Does anyone has an idea?

Thanks.

rq

Hi,
I get the following output when running decomposePar. Would that mean something important ?
Another question : In the ErgunTestMPI/DEM/post I get just the dump.liggghts_restart . Is that OK ?
And the last one : Is there a way of showing particles and fluids VTKs at the same time in paraview ?
Thanks a lot. Alex
amscosta@amscosta-desktop:~/OpenFOAM/amscosta-1.7.x/run/cfdemSolverPiso_shared/ErgunTestMPI/CFD$ decomposePar
/*---------------------------------------------------------------------------*\
| ========= | |

Hi Users,
I am trying to compile CFDEM 2.0.1 release, but could not succeed. First it gives me errors that its missing lmp.h and ......... that I have figured it out by setting the variable in cfdemParticle/etc/bashrc. It gives me the following error at the end.
/usr/lib64/gcc/x86_64-suse-linux/4.4/../../../../x86_64-suse-linux/bin/ld: cannot find -llmp_fedora
collect2: ld returned 1 exit status