CFDEM®coupling - User Forum

This is a forum dedicated to CFDEM®coupling using the LIGGGHTS® DEM code and OpenSource CFD.

Particle disappearing on increasing fluid density

Submitted by aashish.goyal.0110 on Mon, 08/01/2016 - 13:07

Hello everyone,

I am simulating a simple case of particle flow in horizontal pipe with fluid as continuum phase. Now considering two cases:

Case 1: Fluid density = 100 kg/m3
Case 2: Fluid density = 900 kg/m3

All other parameters are same in both the cases. I am able to run the Case 1; but while running Case 2, particles are disappearing from the pipe after a certain distance from the inlet factory (as shown in the Case2.gif).

reconstructPar - cfdemsolverIB

mbaldini's picture
Submitted by mbaldini on Wed, 07/27/2016 - 21:57

Hi I'm running the twoSpheresGlowinski, everithing is OK but I i'm not able to reconstruct the case, I get the following error message.

####################################################################################################################################################################################################################################
Reconstructing fields for mesh region0

Time = 0.003

--> FOAM FATAL IO ERROR:
cannot find file

Taxonomy upgrade extras:

Error when compiling CFDEM

Submitted by yidongxia on Wed, 07/27/2016 - 17:47

Hi,

I am a new user of CFDEM. I use Linux Mint 17.3. To install CFDEM, I first installed OpenFOAM as recommended using git, and then followed to install LIGGGHTS and CFDEM. However, some errors show up as below when I complied CFDEM. Apparently, it seems "CFDEM/CFDEMcoupling-PUBLIC-dev/src/lagrangian/cfdemParticle/etc/additionalLibs_dev" does not exist. But what I have in that directory is
additionalLibs_2.4.x
additionalLibs_3.0.x
additionalLibs_3.2

Superficial velocity or real fluid velocity in GidaspowDrag.C

Submitted by dbxmcf on Wed, 07/27/2016 - 04:44

Hi, All:

I am a bit confused about the Equations used to calculate the drag force term in GidaspowDrag.C:

https://github.com/CFDEMproject/CFDEMcoupling-PUBLIC/blob/master/src/lag...

in line 195:

Ufluid = U_[cellI];

Is this the superficial velocity (U_superficial = U_real*voidfraction) or the real fluid velocity? From my understanding it is real velocity, is that correct?

Wall stress problem

Submitted by ullassssss on Thu, 07/14/2016 - 08:46

I have inserted particles with young's modulus 1e5 into a cylindrical container and obtained the wall stress. Actual young's modulus of the particle is 1.2 e11. Since I was not able to insert particles with this youngs modulus I intensionally reduced young's modulus and hence im getting reduced wall stress. Is there any factor to be multiplied with the obtained stress to get the actual stress? What is the correlation between these two parameters?
Thanking you

Ullas

cfdemSolverPisoScalar vs cfdemSolverPisoSTM

Submitted by yesaswi92 on Mon, 07/11/2016 - 18:20

Hi,

I am new to cfdem and I am going through the tutorials. There are two separate folders, one for cfdemSolverPisoScalar and cfdemSolverPisoSTM. Both of them have similar case - packedBedTemp. The shell script files for both the tutorials are also similar, except for the solver used. In fact, they both give similar results. So, I'd like to know what is the different between these two solvers and how to know, which one to use for a specific case.

Thank You,
Yesaswi

young's modulus problem

Submitted by ullassssss on Fri, 07/08/2016 - 13:59

I have inserted particles with young's modulus 1e5 into a cylindrical container and obtained the wall stress. Actual young's modulus of the particle is 1.2 e11. Since I was not able to insert particles with this youngs modulus I intensionally reduced young's modulus and hence im getting reduced wall stress. Is there any factor to be multiplied with the obtained stress to get the actual stress? What is the correlation between these two parameters?
Thanking you

Ullas

how to run CFDEM tutorial cases in serial

Submitted by zhuang on Thu, 07/07/2016 - 17:13

hi, all-

Sorry if this is a stupid question. I've run tutorial cases like ErgunTestMPI in cfdemSolverPiso and twoSpheresGlowinskiMPI in cfdemSolverIB. Both of them can be run in parallel (like 4 cores or 2 cores) with no problem.

However, when I tried to run them in only one core (in serial), I got errors as below:

--> FOAM FATAL ERROR:
bool IPstream::init(int& argc, char**& argv) : attempt to run parallel on 1 processor

From function UPstream::init(int& argc, char**& argv)
in file UPstream.C at line 79.

Error while running a pneumatic conveying problem

Submitted by vikultomar on Wed, 07/06/2016 - 21:39

I am trying to simulate a pneumatic conveying problem but the particles are not moving with the air, the simulation got crashed very quickly, I am getting the following error:
I have tried with changing the density or particles, the velocity of air in OpenFOAM, if anyone can help me, I'll be really thankful, I have attached the LIGGGHT file and couplingproperties and controlDict files.

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