Symmetry plane for LES in channel
 

Hi,

is it possible to use a symmetry boundary for a plane channel LES calculation on the sides or does it influence the development of the flow too much? Would be nice, if someone has an explanation.

Flo

Re: Symmetry plane for LES in channel
 

A symmetry plane in this case would essentially act like an inviscid wall. So, the velocity perturbations normal to this boundary will be zero and there will be a region near it where these perturbations ramp up to the expected value. I suppose if the length of your domain in this direction is big enough so that you see a flat region in the boundary-normal velocity perturbation rms and sample for statistics there then you are ok. Why not use periodicity?

Re: Symmetry plane for LES in channel
 

Thanks for the explanation! Flo

Re: Symmetry plane for LES in channel
 

You are artificially restricting your flow in the spanwise direction. You have essentially halved the width of your channel. I don't think this is a good idea. In a real flow, the turbulent eddies would be free to cross this plane, so by restricting them you are altering the physics.