CFDEM®coupling - User Forum

In the couplingProperties file, I did not choose any drag force models, but when I run the simulation and use the LIGGGHTS
input script to dump the drag force, found the drag force is not equal 0.

Hi everyone,

Hi All,

Does anyone please let me know how to update the version of LIGGGHTS? The current version for me is LIGGGHTS 1.5.3 based on lammps-10Mar10, which is installed last year. And I have not been used it for a long time. Recently, I need to pick them up again, and the newest version is LIGGGHTS 2.3. And I tried to use "git pull" command under the directory of "LIGGGHTS-PUBLIC" to update it, but it shows "Already up-to-date".

One problem for the old version of liggghts is running the test examples of CFDEM. In the terminal, it shows

Hi everyone,
I try to coupling results from the restart file, however, it shows an error as "WARNING: Restart file used different # of processors (read_restart.cpp:517)
WARNING: Restart file used different boundary settings, using restart file values (read_restart.cpp:588)
orthogonal box = (-0.5 -0.5 0) to (0.5 0.5 0.5)
1 by 2 by 1 MPI processor grid
ERROR: Invalid bond style (force.cpp:280)". Is it related to the coupling properties or the liggghtsCommand? Does anyone know how to modify it? Any help would be thankful.

Dear all,

first test with OF 2.2.x look promising (compilation and first test runs work fine).
I experienced that the probes utilities now write to Case/CFD/postProcessing/probes, which demands the paths in Case/CFD/octave/*.m to be adapted accordingly.

Please keep us posted if you experience problems with CFDEMcoupling 2.5.1 and OF2.2.x.

Kind Regards,
Chris

Hi everyone,

I am trying to see the velocity of one particle with coupling and I modified the liggghts input and the related changes of the tutorials of SettingtimeMPI. However, the results for the cupling are all zero. I attached my liggghts script and the results file. Does anyone know how to modified it? Is it related to coupling properties? Thank you.

Hi

A professor at my university has brought to my attention that if the momentum transfer term, involving Ksl, is computed as occupying an entire single cell, in which a particle is located i.e. for an unresolved case (particle << cells), this could lead to significant flow evolution errors with simulation time. Is this concern valid? And what additional flags or options are required use to produce best flow modulation results.

Also is this concern also valid (if valid at all) for dilute systems?

Thanks

Hi,
I used OF and LAMMPS before, but I am quite new to LIGGGHTS and the CFDEM coupling.
I successfully compiled OF and ParaView and configures the paths.
The system test and the LIGGGHTS compillations seem to work fine, but I cannot get the CFDEM-couling compilled.
Below a more detailed description of the error messages. Any help and hints are appreciated.

Thanks a lot
hansjoerg

While compiling CFDEM 2.5.1, there are many error info when comes to "compile solvers"

---> mkdir: cannot create directory `': No such file or directory......

I simulate the bubbles move up in the water where bubbles are regarded as the discrete phase. In the default solver, the p field is not include gravity effect. Now I add gravity effect in the p formulation and compile the solver. When I run the simulation wihout drag force, I think the gradP force works fine, but if I add the drag force, bubbles don't move up and their movement become out of order. I don't kown what is wrong with it, It's the solver problem or wrong initial conditions or any other problem?anther problem is that some bubbles can cross the draft tube wall.