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-   -   [waves2Foam] Turbulence problems, possibly due to density issues (https://www.cfd-online.com/Forums/openfoam-community-contributions/205894-turbulence-problems-possibly-due-density-issues.html)

app1e December 5, 2015 08:34

Turbulence problems, possibly due to density issues
 
Hi ngj,
Thanks for the powerful tool.
I got the desired result when I generated wave using laminar.But when i switch to turbulence model,say RNG k-epsilon,the surface elevation at a certain probe decays significantly.I think the problem maybe the missing of density term in the k&epsilon equations afterI read your phd thesis (N. G. Jacobsen 2011. ) and the post below:
Quote:

Originally Posted by ngj (Post 371587)
Hi Nima,

Well the short answer is yes that turbulence models have been coupled with waveFoam, however, if you strictly stick to the turbulence formulations in OpenFoam, you will get poor results, as the turbulence formulation in OF does not consider the density in the equations, hence excessive diffusion of turbulence takes place over the interface, which results in rapid decay in the wave height.

Therefore, you need to formulate the turbulence equations correctly, namely including density in the turbulence equations.

Best regards,

Niels



So is there any guide to modify the turbulence equations as I am not familia with the C++..:)
Thank you in advance
Aloha

ngj December 6, 2015 15:20

Good evening,

@Aloha: No, there is no guide available that described how to include the density in the turbulence closure. Please verify that the scale of your problem actually requires a turbulence model.

Kind regards,

Niels


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