CFDEM®coupling - User Forum

Dear all,

I want to simulate the process of a single sphere settling from air to water.

The question I want to ask is whether we can simulate the interaction of air, water and particles in the public version of CFDEM coupling 3.8? As I see from this post, https://www.cfdem.com/cfd-dem-coupled-vof. This function is not open to the public. I just want to make sure whether this function is free now or how we can use this function?

Any clues about such three phases interaction are greatly appreciated.

Hi all,
I am trying to simulate the single particle falling under gravity.
As a base case I took twoParticleGlowinski case, which uses IB method for particle.
In my case the particle also rotating with certain angular velocity.
the simulation is running fine but when I track the particle position I found that some part of particle is going inside
the wall (i.e. wall normal distance of particle center is less than its radius)

Hello All,

Dear all,

Have anyone checked the formula of Di Felice drag force used in CFDEM pavkage?

As I see from the source code (DiFeliceDrag.C) and the refered paper Zhou et al. (2010), the drag coefficient is calculated as:
dragCoefficient=0.125*Cd*rho*M_PI*ds*ds*pow(voidfraction,(2-Xi))*magUr.

However, as I see from Di Felice (1994), the power law coefficient is -Xi while not (2-Xi). In fact, In the literature, there are several variations for the power law coefficient, including 2-Xi (Zhou et al, 2010), -Xi (Felice, 1994), 1-Xi (used in Xu et al, 2000).

Dear CFDEM community,

Has anyone used the smoothing model in CFDEM before? I wonder what's the theory or underlying science for the smoothing approach used in CFDEM?

What I get from the code is that it solves a diffusion equation for the void fraction and the momentum exchange term Ksl.

******************************************************************************
double deltaT = vSmoothField_.mesh().time().deltaTValue();
DT_.value() = smoothingLength_.value() * smoothingLength_.value() / deltaT;

Hi,

Just a quick question, what is the difference between the drag force (Di Felice, 1994) and viscous force used in CFDEM coupling? I am considering the vscous force may be incorporated in the drag force, am I correct?

Best,
Rachel

Hello,

How far away is the public release of superquadric CFD-DEM?

Greetings, Paul

Dear all,

I am a beginner in LIGGGHTS

I am trying to simulate the sediment transport around the pile based
on the reference paper "Shim, J., Duan, J., & Jo, H. (2016).
Simulating Sediment Transport around a Bridge Pier Using Open FOAM
Software. In World Environmental and Water Resources Congress 2016
(pp. 362-369)".

This paper validates by comparing between the simulated the sediment transport and experiment around the pier using CFDEM coupling.

Reynolds number is about 1.8e4. it is laminar flow.

Hello everyone,

I am getting an unphysical pressure field for a few fluidized bed simulations. Everything else (velocity, voidage) seems fine. For most inlet gas velocities, simulations give expected value of pressure. However, for certain flowrate the values are erratic or even negative (possible but not expected) and are so throughout the bed. I am surprised with such fluctuating pressure field how is solution converging?

I am newer of CFDEM, there is a mistake when I run Tutorials. I always get this line:
rm: cannot remove '/home/administrator/CFDEM/administrator-PUBLIC-5.0/run/fillCylinder/CFD/0.*': No such file or directory

and that is the whole running process:
mesh was built before - using old mesh

// run_liggghts_fillCylinder_DEM //

/home/administrator/CFDEM/administrator-PUBLIC-5.0/run/fillCylinder/DEM