CFDEM®coupling - User Forum

Hi

What does DNUM 0 in solver output stand for? Is it okay to get this output?

Cheers
Claudio

Hi

I'm testing the adjustments in the couplingProperties-File. Some questions arose while working.
1) When I use the voidFractionModel centre the momentum coming from the particles in each cell act as one force on the fluid, right? And the momentum acting on the particles is the same for each particle?
2) What is the divided model for? When I try to use this (with dividedProps) I get an error message "type divided, constructor not in hash table". Do I have to compile something again?

Dear all,

For now, please use:

GONIVA, C., KLOSS, C., HAGER,A. and PIRKER, S. (2010): "An Open Source CFD-DEM Perspective", Proc. of OpenFOAM Workshop, Göteborg, June 22.-24.

as refereence if you wish to cite the CFDEM coupling. You will find it freely available by using a search engine.
(http://web.student.chalmers.se/groups/ofw5/Papers/ChristophGonivaPaperOF...)

A newer publication is:

Dear CFDEMers,

I am exciting to join this project from another open source software-MFIX.
From google, some useful materials on the coupling have been got.
Several weeks's efforts on the test didn't show me a approving result compare with the result of MFIX.
Has somebody of this forum got some excellent results using cfdem?
perhaps some meaningful suggestions and experience on the use of this project you give can ease our life.

Thanking you in anticipation for answer.
Best,
Oliver pasqual

Hi Chris,

I found in the release history that

+ new functionality to allow adding forces only to DEM integration (not to momentum exchange terms)

May I ask how to implement this?
I guess to use the variable DEMForces.

So I can give a value to both of DEMForces and impForces.
Then DEMForces+impForces will be applied to DEM and impForces will be used in fluid phase.

Please let me know if I'm wrong.

Thank you in advance.

rq

hello cfdemers,

some questions arise when I use the cfdem, hope you can give me some suggestions.

#question on pressure drop
As we know, change of pressure drop with inlet velocity is used to test the minimum fluidized velocity when justify whether the simulation is correct.
So I take a test using probe and pressureDrop function in controldict.
the simulation parameters are:
volume:60mm*60mm*600, x y z
grid:8*8*60, x y z
particle diameter:4mm
particle number:15660
particle density:2700kg/m^3
minimum fluidized velocity:1.77m/s

and two probe locations are used:

Dear CFDEMers

Starting from the settlingTestMPI I build up a case with 729 particles with diam 0.001 in a 0.1x0.01x0.01 simulation box. On the left side of the box there is an Inlet with vmean=1 and on the right side an outlet with p=0. For the box and the particles the Re is <1 which implies the flow is laminar. Running liggghts and OpenFOAM separately there are no problems. I checked the timestep in liggghts with fix check/timestep/gran.

Hi Chris,

I found the virtual mass model will crash if the number of the particles are greater than 64.

I locate the line of crash is at line 118:
UrelOld_[index][j] = Ur[j];

Do you have any idea?

Thanks.

rq

Hi Chris,

I think the dummy density bug is still in the solver code, i.e.

Line 81 of cfdemSolverPiso.C should be

Ksl.internalField() = particleCloud.momCoupleM(0).impMomSource()/rho;

Please check it.

Thanks.

rq

Hi,

I want to implement a simulation of viscoelastic flow that consists of a polymer melt with suspensed microscale particles . Does CFDEM have the module for viscoelastic flow?

AC