SimScale CAE Forum

Why MRF doesnt work in my project?


#1

I dont understand why MRFZone doesnt work in my project. Would be about the mesh refinements?
https://www.simscale.com/projects/arbstudio/twin_towers/


#2

Hi @arbstudio!

It is always recommended to enclose the domain that is going to rotate - in your case a cylinder around your moving object would work.

Best,

Jousef


#3

Hi, Jousefm! Thank you for your reply!
In simulation-3, I have a mesh with cilinder around the rotor, and still doesnt work, i really dont understand what’s happening. I’m almost give up! I read all the tutorial about rotating geometries


#4

Hi @arbstudio!

Make sure to read this documentation entry: SnappyHexMesh - MRF Zone. As far as I can see you have not defined a cell zone for your mesh.

Cheers,

Jousef


#5

Thanks again Jousefm!!!
At meshe “edificio_024_r4” was created a surface refinement with cell zone inside from solid 74 in of the CAD model, that’s not it? the name must be MRF?


#6

Hi @arbstudio!

The name does not need to be MRF it can be arbitrarily chosen. Also the run seems to be fine without any errors and having a look at the setup it looks as if you have done the right thing. Do you think that your results are messed up? Do you have reference data to compare with?

Best,

Jousef


#7

No I dont. However I’m trying a run with slower speed and more rotation. The main idea is to see the twist in the streamlines. Maybe at 5 m/s is too much for the scale model.


#8

I will give it a spin as soon as I am at home :slight_smile:

Cheers,

Jousef


#9

@arbstudio,

I saw that you already did some simulation. Before I do one - did you make any improvements so far and can you see the streamlines you wished for?

Best,

Jousef


#10

Hi Jousefm!
I think it is a problem about dimensional analysis. Ex: Calculate the wind speed and rotor speed correctly, proportional to the scale of the model. However i think that MRF it’s working.
Thank you one more time!