CFDEM®coupling - User Forum

Hi, everyone,
I faced a paper in the featured work part on the cfdem website:
https://www.cfdem.com/featured-work
which is:
"Fully resolved simulations of particle-laden viscoelastic fluids using an immersed boundary method"
The question is how it is possible to use cfdemSolverIB method for a non-Newtonian fluid? I think someone should answer my question as I faced some non-newtonian papers using cfdemSolverIB. However, this solver just has been modified for Newtonian rheology!

Hi everyone, I am struggling with the following simulation.

I want to simulate a rectangular cavity (of 15.6x5.2x1 cm3) fully filled with 1mm spherical particles with an outlet orifice. The particles should be exposed to a constant pressure of ~1000psi(equivalent to 7e6 Pa) while water is injected on the other side of the cavity. For that reason I settled a servo command like:

fix cad2 all mesh/surface/stress/servo file ../DEM/cad/mwall.stl type 1 com 0.075 0.025 0.0 ctrlPV force axis 0. 0. 1. target_val 56000 vel_max 0.005 kp 5

Hello, I have modified the packedBedTemp case of the cfdemSolverPisoScalar solver. In the modified case particles are pre-fed (in.liggghts_init) on one side of a cylindrical furnace rotating on horizontal axis. The inlet, outlet face, wall and interior of the cylinder have predefined temperatures (as set in CFD and DEM files). The target of the simulation is to obtain the temperature profile of the particles. A typical simulation animation (change extension to .avi) is shown in the attachment.

Hello guys, need some help.

Currently, I am doing simulation in LIGGGHTS. My particles insertion area and surface have height approximately 0.02 in si units.

I would like to add some random height so that my particles drop from different height in the same simulations. Purpose of this is to bring noise on heights.

So I want to drop particles randomly at the height of 0.02 +- 10 % or 0.02 +- 20 %while running simulation.

Is it possible to add this idea in liggghts script?

What will be the command?

Thank you.

Hi everyone,
did anyone do a simulation with cfdemSolverIB and high viscosity values? When I use viscosity values like 10 for moderate Reynolds numbers, the code does not converge and even the Glowinski problem does not give a proper result. So can you please give me some hints concerning this issue?
Cheers,
Mohammad

Hi All,

I am a beginner of CFDEM. It seems like we need to create an Allrun.sh script file to run to a simulation. But I could not find any documents or tutorials about writing this Allrun script. I have looked the code in Allrun files in many tutorials, and they all have some differences. So it makes it hard for me to understand and modify those Allrun files for my own simulations. Hope you can help with it.

Thanks and Regards,

Dear all,

When I get started to run those examples in tutorals, I always get following errors:

CFDEMcoupling version: cfdem-3.8.1
, compatible to LIGGGHTS version: 3.8.0
, compatible to OF version and build: 5.x-commit-538044ac05c4672b37c7df607dca1116fa88df88

You are currently using:
OF version: 5.0
OF build: 5.0
CFDEM build:

Dear all
I am using CFDEM to study the seepage in sand, and I want to use the ratio between the fluid velocity and the particle velocity to distinguish different particle groups, how can i do to achieve that? It seems that the there is no exsist liggghts command which can be used to access the fluid velocity directly?
Zhang Peiyun

I am trying to use a adforce command to apply a stoke's drag force on a single particle using the following syntax

atom_style granular
atom_modify map array
communicate single vel yes

boundary f f f
newton off
units si
#region reg sphere 0.1 0.1 0.1 0.4 side out
#region reg block -0.05 0.05 -0.05 0.05 0. 0.15 units box
#create_box 1 reg
region reg block -0.005 0.005 -0.005 0.005 0.000 0.002 units box

read_data velo

#processors 2 2 1

Hello everyone!! I am new to DEM and CFD. I have been using LIGGGHTS for past few months. I want to model the melting and solidification of powder bed as in Selective Laser Melting(SLM) or Laser Powder Bed Fusion(LPBF). From the papers which I have read, I came to know that it can be done using CFDEM coupling. I started just with LIGGGHTS and have been able to model the powder bed. Now I want to move forward with melting and solidification. Any help in this direction would be much appreciated as I am running out of time.