CFDEM®coupling - User Forum

Hi everyone!

I have a question about implementing Di Felice as a UDF drag model (in TFM) in FLUENT.

Would I be giving FLUENT the expression for gas-solid coefficient, K_gs or do I give it the expression for calculating the drag force?

/* compute reynolds no */
re = rho_g*abs_v*diam*vof_g/mu_g;

/* cd and voidage function */
cd = pow(0.63+4.8*sqrt(1/res),2); /* dallavalle */
beta = 4.8-0.65*exp(-0.5*pow(1.5-log10(re),2)); /* which one? */
ge = pow(vof_g,-beta);

Hi everyone,

I have been attempting to look at the functionality of CFDEM in terms of being able to define the temperature (specifically the power density) of a particle that is generating its own head internally. I have a case where there is a large number of particles (1000s to 10,000s) that all have varying power densities, and these powers will change over time. I have been looking at past forum posts, and through the example problems but it appears that this is not something that is possible in CFDEM. I have a couple questions:

Hi everybody, and developers of CFDEM,

Since the difference in hydro-static pressure ( p = ρgh) on the particle surface causes the buoyancy force, and the fluid force acting on the surface of immersed particle is computed in a fully resolved manner by integrating the pressure and viscous stress on the fluid-solid interface:

F = integral_S { -p*I + Tau } dS (on solid boundary)
= integral_V { -grad(p) + mu * laplacian(U) } dv (in solid region)
for in-compressible fluid.

Hello,

I would like to know if the IBvoidfraction model is efficient for multisphere particle template also. I am working on multisphere particles in resolved CFD-DEM and would like to know how efficient the method implemented for the void fraction calculation is for multisphere particles (particle consisting of overlapping spheres).

With regards,
Achuth

Hi all,

I'd like to simulate the case where the only particle influences the fluid (it means the particles do not get any force from the fluid and are in fixed location). I failed with using oneWayVTK coupling, so I tried to find other ways--make zero interaction force.

I used model A for the coupling, so force models used for coupling are DiFeliceDrag, gradPForce, viscForce, and Archimedes forces. To eliminate the force acting on the particle by fluid, I set those value as 0.

For example, I changed drag term to be 0 in 'DiFeliceDrag.C' file, as follows;

Hi All,

I have used "twoWayMPI" as a data exchange model, and now I try to use "oneWayVTK" model. So I changed the 'couplingProperties' file as follows:

//for twoWayMPI//

dataExchangeModel twoWayMPI;

twoWayMPIProps
{
maxNumberOfParticles 10100;
liggghtsPath "../DEM/in.liggghts_bonded";
}

//change these for oneWayVTK//

dataExchangeModel oneWayVTK;

Hallo CFDEM-community,

I have some rather tricky problems refering to the cfdemSoverIB method with two liquids.

For my master thesis I am trying to use the cfdemSolverIB approach (see the Glowinski tutorial) to simulate particles with a second fluid phase. The aim is something like the CFDEM Ergun tutorial (which is done „unresolved“ with one liquid phase) with a bed of particles and two liquids.

Hi guys
I have got an error by cfdemSys test related to the mpirun. Does anyone knows that how can I solve it?
here is the cfdemSysTest result:

Thank you in advane

bash-4.2$ cfdemSysTest

*********************************************
* C F D E M (R) c o u p l i n g *
* *
* by DCS Computing GmbH *
* www.dcs-computing.com *
*********************************************

Hello All,

I am simulating a particle-fluid flow case using cfdemPisoSolver.

Hello,

I just tried to perform a calculation on the cluster.
I modified a script from an OpenFOAM job, but that didn't work.

call looks like:

bsub < file


in file, there are some settings and finally the call of the simulation:

$MPIEXEC $FLAGS_MPI_BATCH Allrun.sh


but this doesn't work

I also tried just to call:
Allrun.sh

The only thing that happens is the decomposePar of the case.
Any hints?

Thank's a lot
Henrik