SimScale CAE Forum

Convergence problems - Nozzle


#1

https://www.simscale.com/projects/pbocca/nozzles/

The big block is the place where the fluid should expand. I’m having convergence problems of all kind unlikely Incise or decrees step time doesn’t help. Any idea to improve convergence?


How to create a Multiphase flow simulation?
#3

Hi @pbocca,

accidently posted a laval nozzle which does not seem to be applicable for your case. In your simulation case of water dispersing into a volume of air, an example with multiphase flows would probably fit your needs.

Some examples for multiphase flows:

You might have a look at those and see how the simulation setup was done there.

Let me know if that helped you.

Cheers,

Jousef


#4

Hi @pbocca, I managed to get your simulation going, at the moment I am on 0.035s out of 0.25 so ill leave overnight.

here is the project link if you wanna see the changes I made:
https://www.simscale.com/workbench?publiclink=5d30ec14-f7ee-49de-91d7-4a4eee6d2cd1

Run 13

I don’t know if this is the perfect setup but it is not crashing after a few iterations as it was before, the main change that got results was just priming the nozzle with water using a primitive subdomain.

I’ll check the results in the morning and follow up here.

Kind regards,
Darren


#5

Hi, I’m checking and applying changes. Thanx for your comments! Let’s see if we can make this thing to work!