CFDEM®coupling - User Forum

Hi cfdemers,

I found the magnitude of Achimedes Buoyancy force is low by the 4th order.

Please check the magnitude of this force.

BTW, I suggest use Achimedes buoyancy force instead of lift force. The latter is often referred to the normal force to ambient flow induced in shear flow.

Thanks.

rqwang

Hi

I am having trouble with stability in my model and I was wondering if anyone can give me some idea as to what is causing the problem.

I have simple laminar flow between two concentric cylinders, initially starting from rest. A moving wall boundary on the inner wall starts moving the fluid, and eventually the whole domain gets "up to speed". The particles in the flow are initially evenly distributed, but as the flow speeds up, the particles start moving towards the outer wall.

Hi users,
I am new to CFDEM. I am good in LIGGGHTS but I dont know how to do with CFDEM. Please can you provide a simple example to illustrate CFDEM? For example, I have run simulation using LIGGGHTS. Now how to write script or what to do so that I can couple and do simulation in CFD? Is there any example file like example file of LIGGGTHS.
Thanks,
Amrita K

Does any one here know how the coupling between the CFD code and the DEM code is done?
I mean, first one have to compute fluid velocity and pressure accounting from volume fraction through mass conservation and momentum equations.
This operation is generally processed by a velocity-pressure coupling algorithm like SIMPLE, PISO, Chorin projection, etc....
Does someone have some insights on this process and specifically how the mass conservation equation accounting the volume fraction is used for this purpose?

Hi,
I got stuck when i run following command ( it is written in installation tutorial "source your ~/.bashrc file with the command:source ~/.bashrc"):

source ~/.bashrc

It can not do anything in terminal and then i can not open terminal later.
When i delete multiple lines written in bashrc then I can use terminal again. These multiples lines are :

#- source OpenFOAM-1.7.x
. $HOME/OpenFOAM/OpenFOAM-1.7.x/etc/bashrc
#- enable parallel compiling
export WM_NCOMPPROCS=2
#- source OpenFOAM-1.7.x
. $HOME/OpenFOAM/OpenFOAM-1.7.x/etc/bashrc
#- enable parallel compiling

Hi CFDEM Developers,
I am working on the coal combustion in OF, I am running a case with around 1500 coal parcels using four way coupling present in OF, But it seems to me it is taking too much. Using 8 processors, it took me a couple of days to simulate the case for 0.5 seconds and it is still running .
I once tried to couple the coal chemistry foam solver with your interface (CFDEM), i come to know some of the complications. I have few questions regarding this.

I have updated Chris's instructions for the CFDEM build process to correspond to the newest OpenFOAM version. Also I installed it on OpenSUSE 11.3 which I haven't seen detailed to date on the forums, so hopefully it will be of interest.

The instructions are tailored to a $HOME installation, however I did actually install it on an NFS-mounted drive for our computational cluster. If anyone is trying to do this and runs into problems I would be happy to provide some pointers based on my installation experience.

Hello

We're trying to compile the solver for the installation of CFDEM but we get the following error:

Hi ,
I am trying to run the Ergun test case for version 2.0.2.
I just followed :
decomposePar
mpirun
reconstrucPar
foamToVTK
cd ../DEM
However the pizza could not generate the vtk_out because
no dump.ligghts_init was generated. There is only the dump.liggghts_restart in
the post directory.

Also the following output is generated :
amscosta@amscosta-desktop:~/OpenFOAM/amscosta-1.7.x/run/cfdemSolverPiso_shared/ErgunTestMPI/CFD$ decomposePar
/*---------------------------------------------------------------------------*\

Hi,
Any help is very welcome.
I just downloaded the new beta version.
The src is compiling fine. However when compiling the solver, that compiled fine for the june/11 version, the following is displayed :
amscosta@amscosta-desktop:~/OpenFOAM/amscosta-1.7.x/applications/solvers/cfdemSolverPiso_shared$ wmake
Making dependency list for source file cfdemSolverPiso.C
could not open file RASModel.H for source file cfdemSolverPiso.C