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-   -   Turbulence modelling in OpenFoam (http://www.cfd-online.com/Forums/openfoam-solving/113193-turbulence-modelling-openfoam.html)

nore5 February 14, 2013 11:22

Turbulence modelling in OpenFoam
 
Hello,

I find some difficulties defining the right parameters related to turbulence modelling in OpenFoam. in fact, I tried to follow the same steps available in the user guide to set a turbulence model but the result is always the same, my simulations /when I set up a case from scratch/ crash with very high bounding values of turbulence parameters after the first time steps.

How can I learn how to set up an accurate turbulence model please? I can t find a tutorial that focuses on that in particular / a part from user guide/...


Any advice and guidelines are welcome too.

Thanks in advance.

Nore

Lieven February 14, 2013 13:38

Hi Nore,

Are you using RANS or LES?

Often this type of crash is caused by a bad initial condition or/and by (incompatible) boundary conditions. One 'trick' that can help obtaining better initial conditions is by running potentialFoam first for a number of time steps...

Cheers,

L

chegdan February 14, 2013 16:31

For RANS-based simulations ( and you're sure your boundary conditions are correct), in addition to potentialFoam as an initial condition you can:
  • Use upwind schemes to start with
  • Run the turbulent case with the laminar model first, then turn on turbulence mid simulation
  • use the converged first order result as an initial condition for higher order schemes

These are just some quick tips.

nore5 February 15, 2013 15:04

Dan and Lieven thank you for these hints.

I will try to apply it to a case and see what happens.

BUT how to make sure the BC are the right ones too please?

Thanks again.


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