CFDEM®coupling - User Forum

Hello, I am trying to change si scale to cgs. I made the change in liggghts side and in OF part, but I am having some different behaviours. I run the settlingTestMPI using two different values for the kinematic viscosity in both cases and plotted v_y velociy as a function of time.
In liggghts side I changed unit, diameter, density, gravity and young modulus.

Hello, I am sorry if this a too basic question, but I am trying to understand what each parameter in the twoSpheresGlow... tutorial does and I am having some problems. Basically if I remove gravity in the DEM part particles start to go up instead of going down and that has sense because lift force. But, DEM is in "si" units and CFD is too. I added a rho file to CFD/0 folder and rho is equal to the density of the DEM particles but particles still move up. So, my questions are: Is there other field affecting the system? does rho internal field equal 1.5 mean fluid density equal 1.5?

Hi,
Though downscaling from 3d to 2d cannot be performed properly in CFDEM simulations, as some of the feature still consider the atom type to be sphere rather than a disk, there are times which one just wants to check whether a concept would work or not, and an initial 2d simulation would be sufficient. I’ve checked the following link on steps to take for performing 2d simulations
http://www.cfdem.com/media/DEM/docu/Section_howto.html

Hello all

I have a Suse Enterprise cluster system where LIGGGHTS-3.0.6 and OpenFOAM-3.0.x are successfully installed. Third-party gcc-4.8.1 was used to compile LIGGGHTS by Makefile.g++ file and OpenFOAM.

I have compiled openfoam-3.0.x and LIGGGHTS but CFDEM throws error while compilation (cfdemCompCFDEM). Please help me

I can provide any information you want.

Thanks,
Siva

Hi there,

I am now using CFDEM to simulate a simple liquid-solid fluidized bed with a void fraction of 0.53. I used the divided void fraction model. However, the void fraction close to the inlet I got were close to 1 which caused the bottom particles staying nearly still. Please kindly find attached the image of the void fraction.

Hello,

the new CFDEM(R)coupling version 3.6.0 was released yesterday - please let me me know if everything works fine for you.

Best regards,

Christoph Goniva

Hi,
I was wondering how can I run a case using explicitCoupling. I understand that implicit coupling provides better stability, but based on what I've been reading in the literature the explicit coupling is more accurate. So referring to the settling case tutorial, cfdemSolverPiso/settlingTestMPI, I made the following adjustments in constant/couplingProperties:

//--------------------------------------------------------------------
momCoupleModels
(
explicitCouple
//implicitCouple
);

I see that fvOptions are supported by cfdemSolverIB, or at least it appears to be the case from looking at the source code. Are there plans to add fvOptions support to cfdemSolverPiso as well?

I am trying to run a case of oscillatory flow using a tabulatedAccelerationSource in fvOptions to drive the fluid, which works with pisoFoam, but didn't do anything in cfdemSolverPiso.

Hi all,