CFDEM®coupling - User Forum

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.

I am using compute like this

compute kash all property/atom z

compute kashi all property/atom x

compute kish all property/atom y

variable b equal c_kash[1]

variable p equal c_kashi[1] #r

And I am getting an error "Compute used in variable between runs is not current. Use the update_on_run_end option for computes to avoid this". I want to Know how and where to use the update_on_run_end option. in Variable command or in compute command above variable.

Hello all,
I work on shear fault and I would like to use LIGGGHTS to simulate it. Files (.stl and in.) are in the attachments.
Currently top and bottom plates are smooth but I would like to have rough one.
I would like to glue particles with those plate before shearing.
I have downloaded LIGGGHTS_Flexible_Fibers version and I would like to know if it is possible to glue particles and mesh. And if it is possible how.
I stay available
Regards

Alexandre Sac--Morane

Hello LIGGGHTS forum, I am trying to run a simulation in an inclined surface. Till now my script is working nicely.
I want to add viscous and damp command in my script.

When ever I added it as ` fix 1 viscous 0.1 ` or `fix 1 damp viscous 0.5 scale 3 2.5` I got following message.
```
ERROR: Could not find fix group ID

```

I also tried to add as `fix m6 viscous...` got the same error.

How do I add them correctly?

Any help would be appreciated.

Thanks a lot.

My script

```

# Initialize

Hi all,

As we can see, until now, the public version of CFD-DEM scheme cannot be used to coupling simulation considering particle shape. To realise this function, the easiest way may be using bonded multi-sphere modes to simulate particle shape, while not using superquadric function. Also, the solid-fluid interaction forces, e.g. drag force model, should also be modified. My confusion are:

Greetings,

I need to create a scalar wich give me as result the concentration of particle per cell. This post of the forum did it (https://www.cfdem.com/forums/fluidized-bed-chemical-reactors). Could someone help me replicate it in my simulation?
It seems that need to compite something.

Thank you already,
Kesley A. Santos

Greetings,

What does mean vSmoothField and sSmoothField?

Hi,
I am working on cfdemSolverIB and I have obtained good results for multiple Newtonian cases. However, I want to implement the Herschel-Bulkley non-Newtonian fluid model in my fluid field, which I faced some noteworthy issues.
We know that in Newtonian cases for cfdemSolverIB, based on the Patankar IB method, the particle velocity imposing in the fluid velocity field is equal to considering the below source term in NS equation:
rho*d(ubar-u)/dt

Dear Ladies and Gentlemen,

I plan to modify the hertz model to consider diffusion.

So I work in the script of the model normal_model_hertz.

How can I use this model in liggghts? my plan is to insert my new script in the src folder.
How can I assign this contact model in my script?
Which command I have to use to in my liggghts script, to use this model instead of the hertz model?
How can I implement and load my new model in the liggghts library?

So far I use this command to use the hertz Model:

Hello Team, is there any document or guidelines on best practices to set up a CFDEM case? For example, cell size estimation from particle size, coupling interval for inertial and kinetic flows. Perhaps, we all want our simulations to be as accurate as possible. Thank you.