CFDEM®coupling - User Forum

Hi

I am running a coupled simulation with cfdemSolverPiso_shared. My model runs fine when only run on 2 processors. I want to see if I can speed up the run, and so have tried running it on 4 processors. However, my simulation crashes at the first CFD timestep (LIGGGHTS initialises fine, and inserts the correct amount of particles) and produces this error:

Starting time loop

Time = 0.0001

[0] #0 Foam::error::printStack(Foam::Ostream&) in "/home/cerecam/OpenFOAM/OpenFOAM-2.0.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"

Hello

I've installed CFDEM with OF-2.0.x as described in the installation-guide from CFDEM. But at the end i tried to run the cfdem testcase. The Allrun.sh script didn't run well. I could not visualize the results in paraview. I'm a bit experienced with OpenFOAM and there it works well with the ParaViewer.
My first question: is there something wrong with the Allrun.sh shellscript?

I also tried to run the case without Allrun.sh (cf CFD, decomposePar, ...). But this workflow also failed. When I run pizza I get the message:
error on line 1 of file ./pizzaScriptInit

hi everyone,
i am new on cfdem. i have jst installed cfdem with openfoam and liggghts coupling. is there any manual so that i may learn step by step commands for running cfdem over gas-solid fluidized bed.
thnx

Hi everyone,

I am new to OpenFoam, and have already installed the new version. I would like to run the coupled DEM-CFD code, however ,I do not know where to find the coupled DEM-CFD code, and how to compile it. I would appreciate any help.

thanks
Vajiheh

Hi guys, I'm running onto a problem while trying to compile CFDEM...

First of all, yes, I compiled OF 2.0.1 from scratch... re-compiled it again, compiled liggghts, the libraries, checked that I am using the same compilers, edited the .bashrc at /etc , and I am having this error on twoWayMPI.C... By the way, on Mac OS x S.L. 10.6.8...

I guess that I am having some sort of problem with the including of liggghts libraries, so I am trying re-make-ing liggghts with different options.

I have installed Liggghtts, OPenFOAM, and on my way to install cfdem.

(1) In the instruction, there is a step to copy into $FOAM/run below. But the OpenFoam I installed has no run /subdirectory.
Should I create one, then copy into?
----------------------------------
copy cfdemSolverPisoCase_shared/* to /home/user/OpenFOAM-1.7.1/user-1.7.1/run/cfdemSolverPiso_shared
----------------------------------

(2) Also not clear is that, two other copies, such as:
copy cfdemSolverPiso_shared to /home/user/OpenFOAM-1.7.1/user-1.7.1/applications/solvers
Should it be

Hi Chris,

Is the fluid stress gradient force under development?

This force is taking account the effect that if no solid particle exists, how much force the fluid parcel is bearing.

In this way, if the particle has the same density as the fluid, it will purely trace the flow.

Thanks.

rq

hello everyone,
I have a question of the implementation of DiFelice drag model in cfd-dem.
the code detail is:
if (magUr > 0)
{
// calc particle Re Nr
Rep = ds*voidfraction*magUr/nuf;

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

// calc model coefficient Xi
scalar Xi = 3.7 - 0.65 * exp(-sqr(1.5-log10(Rep))/2);

// calc particle's drag

Hi, cfdemers,

I am using a very dense gridmesh.
When I simulate a single particle settling in water, all the momentum induced by the particle seems to transfer into one single cell.

Is there any way to disperse the induced momentum into a large area.

In another words, is it possible not to restrict the induced momentum in a single cell, but by some averaging model like PSI-cell method?

Thanks.

rq

Hi every one,

I tried to run a settling simulation (similar to the settlingTestMPI) with the IB-Solver and found that the particle doesnt settle as it should be (Stokes as comparison). So I had a look at the calculation of the drag force and I think there is a mistake in the equations.

(1) volVectorField h = nufField*fvc::laplacian(U_)-fvc::grad(p_);
...
(2) drag += h[cellI]*h.mesh().V()[cellI];

I think both terms in equation (1) (nufField*fvc::laplacian(U_) and fvc::grad(p_)) should be multiplied with the density of the fluid.