CFDEM®coupling - User Forum

Dear all, for the CFDEM now, can we consider the Basset history force for the particles now?

Thank you so much!

Detian

Hello all,

I am trying to study how the fluid flow velocity could influence (decrease) the temperature of particles.

I found some information about particle-particle and fluid-particle heat transfer but in my case I disregard the temperature of fluid. I only need the flow velocity as a parameter and how this parameter could change the temperature of the particle, I also need this parameter in the future for other purposes.

Hi, All:

Dear CFDEMers,

I set up a case with dynamic Smagorinsky LES model, but I found one thing that, with the smooth case, LES model can give great result, but if I put one layer of sediment (fixed at bottom), the LES model still give the shear velocity u* like smooth wall, but the RANS model (komegaSST model) can recognize the particles and give a larger shear velocity which is close to the experiment.

Has anyone has met the same problem and could give me some advice on this?

Thank you so much!

Detian

hello cfdem community,

i'm trying to run the command cfdemCompCFDEM to couple CFDEM with OpenFOAM-2.4.0 and it doesn't seem to work. Besides the RASModel.H and ompi/ error, the compilation gets stopped at /usr/bin/ld: cannot find -llagrangianCFDEM-PUBLIC-2.4.0. I've attached 3 logs file for your inspection. I've changed a few variables in ~/.bashrc as follows:

Problem Solved

Hi all,

I have a problem running the tutorial case ErgunTestMPI with the following transport property.

transportModel HerschelBulkley;
nu nu [ 0 2 -1 0 0 0 0 ] 1e-04;
rho rho [ 1 -3 0 0 0 0 0 ] 1000;
HerschelBulkleyCoeffs
{
nu0 nu0 [ 0 2 -1 0 0 0 0] 1;
tau0 tau0 [ 0 2 -2 0 0 0 0 ] 1e-03;
k k [ 0 2 -1 0 0 0 0 ] 1e-06;
n n [ 0 0 0 0 0 0 0 ] 1;
}

Hi All,

I have a question about the fix freeze command in CFDEM coupling, as I found it's behavior is different from what's described in the docs (or, I'm doing something wrong, please help me with this:-() . I define particles in a region near the bottom to be type 2, and the other particles to be type 1. in the DEM part, I used the following line to freeze the particles of type 2:

......

group bottom type 2
group active type 1
fix 2 bottom freeze
velocity bottom set 0.0 0.0 0.0 units box

Hello guys,

I want to simulate a small channel (11 micrometers) with small particles (2 micrometers).
Therefore I chose the "CGS" unit system. I tried to build a model with a 11 cm channel and 2 cm particles and it works fine.

But when I scale my region, neighbor, scaling coefficients, velocities, radiuses, blockMeshDict; it doesn't work anymore (Courant number rises very quick).

Dear all,

Recently I have read the code of virtual mass force, but there is a question that:

the original force = 0.5*rho_f*V_p*(Du/Dt-du_s/dt)=0.5*rho_f*V_p*(du/dt+u*div(u)-du_s/dt)

is that means in our virtual mass force model we use:

if splitUrelCalculation, using (Du/Dt) instead of (Du/Dt-du_s/dt),

if not splitUreCalculation, using (Ur-Urold)/dt instead of (Du/Dt-du_s/dt).

Is my understanding of this right?

Thank you!

Detian
2015.7.18