CFDEM®coupling - User Forum

twoSpheresGlowinski

Hi

I am getting confused between the Mei/Saffman lift force and the "viscForce". As far as I can tell, they both depend on the fluid velocity gradient. So won't using both the Saffman force and the viscForce include the same effect twice? Or do they act in different directions?

Can anyone explain what the differences are?

Thanks
Evan

Hi,

I want to know is it possible for me to simulate fluid flow thorough porous media?
If yes, how can I do that?

Thanks for the response in advance.

Hi Chris,

i modified the OpenFoam solver pimpleDyMFoam where the CFDEM scheme is added. It works fine as the orginal solver cfdemSolverPiso, however when i changed in the dynamicMeshDict staticFvMesh ----> dynamicRefineFvMesh, to refine the mesh of certain field, it seems the locateModel can not find the particles after the mesh is refined.

So I wonder, how can we locate the particles in the new refined Mesh?

Best regards,

David

Hello everyone,

There is an error happened when I trying to run an example from tutorial as "--> FOAM FATAL ERROR:
Trying to use the dummy Pstream library.
This dummy library cannot be used in parallel mode

From function UPstream::init(int& argc, char**& argv)
in file UPstream.C at line 37.
--> FOAM FATAL ERROR:
Trying to use the dummy Pstream library.
This dummy library cannot be used in parallel mode

From function UPstream::init(int& argc, char**& argv)
in file UPstream.C at line 37.

Hi Chris,

I wonder how to access the trubulence visicosity nut(). For incomprissble flow, all force models
use:

const volScalarField& nufField = particleCloud_.turbulence().nu();

If a RAS model (e.g k-epsilon) is selected, should we conside thetrubulence visicosity in CFD-DEM? Lets say:

const volScalarField& nufField = particleCloud_.turbulence().nu() + particleCloud_.turbulence->nut();

Furthermore, if there is multi-phase fluid in the Domian, the visicosity is a mixtured value, e.g effective muf:

Everything goes well before I type "cfdemCompCFDEM" in the terminal. I can run both OpenFOAM examples and LIGGGHTS examples successfully.
But errors occur during the CFDEM compiling below:
##################################################################
/home/ciel/OpenFOAM/OpenFOAM-2.2.x/src/OpenFOAM/lnInclude/autoPtrI.H: In member function ‘const T& Foam::autoPtr::operator()() const [with T = Foam::clockModel]’:

Everything goes well before I type "cfdemCompCFDEM" in the terminal. I can run both OpenFOAM examples and LIGGGHTS examples successfully.
But errors occur during the CFDEM compiling below:
##################################################################
/home/ciel/OpenFOAM/OpenFOAM-2.2.x/src/OpenFOAM/lnInclude/autoPtrI.H: In member function ‘const T& Foam::autoPtr::operator()() const [with T = Foam::clockModel]’:

Hello everyone,

I met an error as "Cannot open mesh file ..DEM/b1.stl (input_mesh_tri.cpp:78)" when I run with "bash Allrun.sh". There is a stl file named as b1 in that package and it could run just with DEM. The code I used for importing wall is "fix cad1 all mesh/surface file ..DEM/b1.stl type 2". Is there anything I used to run the test? Does anyone met this error before? Thanks for any recommendation.

Hi CFDEMers,

I wonder whether it's possible to find the upstream and downstream cell index of a particle. I know the particle cellI is the particle's center sits.

For example, if I know the velocity at the particle center is in x positive direction, then the upstream cell is the neighbor one in negative x direction and the downstream one is the positive x direction.

Is there a good way to find the cell index? In addition, is it possible to get the velocity from the upstream one and distribute the momentum (impForces) to the downstream one? Please advise.