CFDEM®coupling - User Forum

Dear all, I have a really basic question regarding the settlingTestMPI tutorial. As far as I understand it simulates the settling of a sphere in a still fluid and compares the simulation results with the analytical Stokes (creeping flow) solution. But I can't find a reference (paper) of the expressions used in the .m scrip. I understand that It performs and explicit integration of the position but I cannot find a reference of the velocity determination.

I've attached bellow the octave script.

Cheers,
Mauro

Dear CFDEM users,
I am running a case in which an STL file as a gate moves up a specific distance and after it stops. So I need to use restart CFDEM.
However, I faced with this error:
Mesh elements have been lost / left the domain. Please use 'boundary m m m' or scale/translate/rotate the mesh or change its dynamics
I modified liggghs command and coupling properties like Erugan_resatart but I do not know why the gate does not stop.
I would be thankful if you help me to solve it.
Best,
Shadi

Dear CFDEM users,
I am working on a case in which I need to use restart CFDEM.
In the case I need to move up a STL file and stop it and running the case with the stoped STL file.
So I did :
First, loading the particles(liggght-init)
Second, using an STL file as a gate which moving up till t=0.05(liggghts_run)
Last, running the case without the gate. (liggghts_restart)
I have a question regarding the controlDict which controls the running time.

Hi,everyone
I have several problems compiling CFDEM. I have tried my best but I can not deal with it...

Backgroud:
1. Because of some reason, I have to compile CFDEM with old version. (CFDEMcoupling 3.0.1, LIGGGHTS 3.5.0 and OpenFoam 3.0.1)
2. I think LIGGGHTS and OpenFoam have been already compiled correctly.
3. The error occured in the step "cfdemCompCFDEMall"

Problem:
At first, I found error in the logfile "log_complog_compileCFDEMcoupling_cfdemSolverPiso". The detail is shown below:

Hi,

I am trying to model liquid and particle flow inside a tank generated due to the rotation of a stirrer inside the tank. The stirrer is rigid and rotates at a constant angular velocity. I need to use dynamic mesh to implement the motion of the stirrer. I am not sure how to implement dynamic mesh in CFDEM-coupling. Can anyone suggest me how to implement dynamic mesh in CFDEM-coupling? Please also let me know if there is any tutorial on dynamic mesh in CFDEM-coupling

Thank you.

with regards,
Hossain

Hi all,

I am new to CFD-DEM area. I want to run the tutorials for ErgunTestMPI. But I got the error:
----------------------------------------------------------------------------------------------------------------------------------------------------
// run_parallel_cfdemSolverPiso_ErgunTestMPI_CFDDEM //

/home/caocd/CFDEM/caocd-PUBLIC-7/run/ErgunTestMPI/CFD

Hi,
I found the calculation of the normal relative velocity did not contain the rotation velocity contribution, which is no consistent with the literature formula.
In surface_model_default.h
// relative translational velocity
const double vr1 = sidata.v_i[0] - sidata.v_j[0];
const double vr2 = sidata.v_i[1] - sidata.v_j[1];
const double vr3 = sidata.v_i[2] - sidata.v_j[2];

Hello Users,

I am trying to solve pneumatic conveying system with dense solid flow regime (void fraction varies from 1 to 0.35), using CFDEM two-way coupled solver. The versions are OpenFoam 5.0 and LIGGGHTS-Public 3.8.0.

Hi,
I want to insert particles at fixed points while CFD is running. I tried using execute in liggghtsCommands for create_atoms with startTime and endTime. But even with the runEveryCouplingStep off, LIGGGHTS creates atoms at each coupling step. How should I create only one atom at t=0.0001s for instance?

DearCFDEM user,
I want to see the CFDEM simulation results in ParaView. But the problem is that it does not show CFD and DEM results at the same time. The particles movement are shown later.
I would be thankful if you could help me.
Best,
Shadi