hi, is there anybody who is using or has used Les in Fluent?I'd like to know a bit more about this model.if there somebody who can help me,lplease contact me. thanks in advance antonietta

The question is what do you want to model....LES is a very havy and costly model.

Describe a little what you want to do.

Hi, I have a combustion simulation performed, in a steady state and now I'd like to apply LES. I'd like to know if : 1) it's correct to apply Les after the steady state has been converged. 2) how small have I to fix the time step size 3) when the les simulations can be considered converged and since this is the first time I approach with LES, every suggestion will be helpful and appreciated.

thanks in advacnce Antonietta

First performing a LES simulation is much more complicated than a RANS simulation....

1) Yes it is good to start LES from a steady state (RANS of course!)

2) consider LES converged if you get enough time data to have constant mean and standard deviation on your results....so it depends.

3)Grid size and time step? this is a 1 0000 000 $ question...How small is small enough?

depends on the reynolds number, the grid should be small enough to catch all non-isotropic structures. The time step should be smaller than the rotation time of your smallest vortices....the time step is then correlated to the grid size...