CFDEM®coupling - User Forum

Hi

I am using solverIB for getting pressure drop and velocity distribution in a packed bed. I have found that the pressure drop and velocity magnitude keeps on increasing as i decrease the cfd timestep. The pressure drop varies from 250 Pa to 10000 Pa as i vary cfd timestep from 10^-4s to 10^-7s. The analytical pressure drop is around 400 Pa. I have adjusted coupling interval accordingly when i vary cfd timestep.

I have found similar queries in the forum but no solution yet. Can somebody help me?

Thanking You
Baju C Joy

Hey Guys,

anyone else came across something like this:
By coincidence I changed the order of the force models in my Coupling Properties file. And even if the difference in the results of both simulations were not significant, there were some (compare Picture 1 and 2 - both were taken after the exact same time in the exact same setup (except the order of the force models))

Hello everyone, I try to do a triaxial test on a soil specimen. When I try to use the servo walls to apply the confining stress on the specimen, a question arises. As the soil is saturated, is the stress on the servo walls total stress or the effective stress? Thank you very much!

Best wishes,
Jack

hi everyone,
Now ,i want to add fvOption file to cfdemIB. First, I called in cfdemIB.C file and then added -lfvoptions to option file. After that, I went to compile my solver, but the error was reported.As follows:
cfdemSolverIB.C:44:29:fatal errror:fvOptions.H:No such file or directory
#include "fvOptions.H"

I have been scouring the internet for an answer to this question and I can't seem to find anyone who has truly dissected it so I'll post the question here. If anyone knows of a paper or forum post that already addresses the following concerns that would, of course, be really helpful.

I was modelling a packed bed using cfdem solverib so that i could get the resolved velocity field. But i have noticed that the pressure residuals after decreasing start to increase and never converge. Can anyone help me solve this problem? The residuals decrease to about 0.2 and then slowly starts increasing. I have tried using relaxation factors but the same thing happens. And the final pressure drop i obtain for the bed after many iterations is not accurate compared to the ergun equation.

Hi All,
My simulation of a heated packed bed is progressing, however I have come across another difference between my CFDEM results and my past results using starccm+. The pressure drop across the pebble bed is expected to be ~550Pa, which is what the experimental results show, as well as mine and another authors simulation results in the past.

Dear All,
I am trying to simulate a small section of the dilute gas-particle flow in a riser.
The boundary conditions for the particle phase were set as periodic boundary in the z direction (boundary m m p). The solids volume fraction is 0.018.
The boundary conditions of incompressible gas phase are: uniform inlet boundary at the bottom (0 0 0.0925) and pressure outlet boundary at the top (zeroGradient). The other boundaries were set as no slip walls.
The solver is cfdemSolverPiso.

Dear community,
I try to install CFDEM latest version and meet problems...See below
Could somebody help me to fix problem? I usem Ubuntu 18.

fura@fura-VirtualBox:~$ cfdemSysTest

*********************************************
* C F D E M (R) c o u p l i n g *
* *
* by DCS Computing GmbH *
* www.dcs-computing.com *
*********************************************

Hi all,

I have been trying to implement a case similar to the packedBedTemp cfdemSolverPisoScalar example case where hot particles are cooled by a flowing continuous phase. For my case I will not know the temperature of the particles, but instead the power (in Watts) of each particle so I am thinking I will need to use the heatSource model instead of the Temperature model within heat/gran. I have read the brief discussion of it in the user manual, but I am having trouble replicating results I have gotten through commercial codes.