Hi evry body, How to introduce DES with Fluent 6.1.18? I have activat Spalart-Allmaras but I don't find turbulence- expert in the panel of viscous models (like it is say in the user guide)!!!

thanks

Dear naus,

You won't find this option in the menus. In Fluent 6.1.22 You have to choose 3d unsteady simulation, the spalart-allmaras model and then you must write in the prompt line:

/define/models/viscous/turbulence-expert/detached-eddy-simulation?

The program will ask you an answer (yes/no?).

Answer yes and detached eddy simulation will be selected. But I don't know if this trick is going to work in 6.1.18.

In case it works, there is a detail that is unknown to many users: in this version of fluent, when DES is selected the program applies the boundary conditions for turbulence fluctuations that are the default for LES, and are pretty high. So, you have a very high level of noise in the simulation. Before selecting the spalart-allmaras model is advisable to select LES and change the inlet boundary conditions for the tubulence fluctuations. Only then you should select spalart-allmaras and activate DES from the prompt line.

Regards,

Fabio