CFDEM®coupling - User Forum

Hi All,

I have already run the coupling test example of the CFDEM. And I am wondering how to watch the result as animiation in the paraview. I notice for the cfdemPostproc, after running, the paraview is open automaticly. But for other case, I have no idea how to do it.

Any suggestions and helps are highly appreciated.

Thanks!

Kun

if(verbose_ && index >=0 && index <2)
{
Info << "index = " << index << endl;
Info << "gradP = " << gradP << endl;
Info << "force = " << force << endl;
}
I wrtie "verbose" under the gradpprop item in the couplingproperties file.

How can I get the data

Is it possible to download CFDEM Coupling software without using git ? We don't use this currently on our cluster. Is there are tar available ?

We have previously built OpenFOAM and LIGGGHTS from source, not using git.

thanks,

Colin

I simulate the bubble's movement in the water and the bubbles are regard as discrete elements. At the start of calculation, the bubble velocity is not equal to 0, and the liquid velocity is equal to 0, the pressure gradient of the liquid flow field is 0, therefore the buoyancy of air bubbles is 0, but the drag force is not 0, So if the bubbles inject into the flow field in the horizontal direction ,they will be move downward under the drag effect, which is obviously not realistic. How to solve this problem?

My case computation takes a lot of time. So I want to kown, If I interrupt the calculation, how to save the results, including CFD and DEM sides, and next time I can continue to compute using the previous calculation results as initial conditions.

For model A simulations, the viscous force is applied in addition to the particular drag model (Schiller Naumann, Koch Hill, DiFelice or Gidaspow). I have read over the paper by Zhou (2010) 'Discrete particle simulation of particle-fluid flow: model formulations and their applicability' and I have seen that this viscous force term is included in their eqn 2.13, the sum of forces on a particle.

I have examined some of the original literature on the drag force models used. Am I correct in stating that when using the Koch Hill drag force model, the Archimedes buoyancy model should NOT be used as it is 'included' in the Koch Hill model by their definition of drag force? Or has the Koch Hill drag force model been modified by a factor of the fluid fraction to 'remove' the buoyancy term?

On the other hand, the Archimedes buoyancy force does need to used when using all the other drag force models, correct?

I have been examining the available drag models available and I have a number of questions. Your time in addressing these is most appreciated.

When examining the Schiller Naumann drag model implementation, the drag term is given by;
drag = 0.125*Cd*rho*M_PI*ds*ds*magUr*Ur
- why is the scalar term 0.125 and not 0.5?

When examining the Koch Hill drag model implementation, the Reynolds number term is given by;
Rep = ds/scale_*voidfraction*magUr/(nuf+SMALL)
- is scale_ = 2? or if not, what is this term?
- what is the SMALL term?

Hi All,

The attached file is the detailed steps for installation of OpenFOAM-2.2.x, LIGGGHTS, and CFDEMcoupling. Hopefully, it does help for the new users.

But, after coupling, it shows
%Note: the list of utilities compiled might be incomplete.
please check /home/cee-student/CFDEM/CFDEMcoupling-PUBLIC-2.2.x/applications/utilities for more utilities available

For the Test case and cfdemSolverIB, it has no problem.

In the DEM inpustscript file, I use the comand:
compute dragtotal all reduce sum f_dragforce[1] f_dragforce[2] f_dragforce[3]
#screen output
compute 1 all erotate/sphere
thermo_style custom step atoms ke c_1 vol c_centerOfMass[3] c_dragtotal[1] c_dragtotal[2] c_dragtotal[3]
thermo 10
thermo_modify lost ignore norm no
compute_modify thermo_temp dynamic yes
#insert the first particles so that dump is not empty
dump myDump all stl 1 ../DEM/post/dump_*.stl
#run 1