CFDEM®coupling - User Forum

Hi all,
I am recently doing research on the CFD-DEM importing superquadric models. Everything is good in the liggghts after I modified some codes as shown in the official announcements, and I successfully finished the superquadric particles packing in the DEM side. However, when I turned to the CFD side and runned CFD, it told "invalid atom style". I tried some ways(such as set "superquadric_flag = 1" in atom.cpp),but it seems of no use. Could anyone give some advice?

Thanks,
Clyde

Hi,
I am looking at the KochHillDrag formulation and have experienced that a variable called "SMALL" is used. However, I have not yet found out what the value of the variable "SMALL" is? I would expect it is just a "small" number, but I am not able to find the exact value?

I hope someone can help me.

Cheers,
Jeppe

Hi all

I am a beginner of CFD-DEM and the particle shape in my simulation is ellipsoid. I am quite confused that what adjustments do I need to make to complete my simulation？

As far as I konw, I need to add new drag force, lift force etc. in the forceModel folder. Is there anything else that needs to be adjusted in CFDEM?

Hello Community

I am facing this strange error when performing CFDEM simulation. I prepare gravel bed in channel cavity by performing pure DEM simulations and then use restart file written in pure DEM simulation to perform a coupled simulation. At the very first time CFD time step, I get error mentioning that Message from processor XX is not fully consumed. I have looked online if someone has faced similar problem but I cpuld not get any similar post. More specifically the error says:

I am using public version of CFDEM to simulate my case. I took referance from periodicChannel case and modified my case in which inlet and outlet are coupled with cyclic boundary and flow velocity is defined using fvOptions located in CFD/system directory. I find it very strange that in the tutorial case *periodicChannel), I dont get any error and case runs smoothly. In opposite to that I get error for my case that model type meanSupVelocityForce is unvalid and the shows a list of fvOption models available. I wonder why is that.

My fvOptions file has following:

Hi Guys

Please refer to the attached input file. I am getting the below error.
The error is at line 55. I am using a prime number for the generation however the error still occurs.
Can someone please assist?

Hi,

I would hear if it is possible to simulate with particles that are non-spherical? At the moment I have only simulated with particles that are spheres. However, I wondered if it is possible to create cubes to simulate with?

Cheers,
Jeppe

Hi all,

I am trying to figure out what the rho value in the 0 folder indicates. In the "Periodic Channel" tutorial case for "cfdemSolverPiso" the rho value is set to 1.3 kg/m^3, however is this the density of the fluid or the particle (neither seems to be realistic values) ? However, in the "settlingTestMPI" and the "voidfractionTest" tutorial cases for the "cfdemSolverPiso" the rho values is set to 10 kg/m^3.

Maybe one of you can help me solving my confusion about the constant rho.

Cheers,
Jeppe

Hi all,

I tried several times to Set environment variables and paths. However, I got the following error:

cfdemSysTest: command not found

I followed previous steps successfully, but I don't know what is the problem here. Also, I read the solutions provided before for this problem and checked the paths, although none of them works.

I use Ubuntu, and LIGGGHTS and OpenFoam work on my system without any problem. Please help me in this regard.

Hi everyone

I am running simulations of a pressure driven suspension flow through a micro channel, investigating particles sized of 1 micron and below in diameter. Because of the size of the particles I am required to use the 'micro' unit system within LIGGGHTS.

In order to get the correct units within OpenFOAM I have adjusted both the units in the constant '0' folder and also added in the similar details from the "ErgunTestMPI_cgs" tutorial case to the controldict file but converted to match the LIGGGHTs micro scale.