Hi Experts, In star CD how to switch on DNS? Thanks in advance.

The obvious question is why do you want to in the first place, its not just a case of "switching DNS on". If you want to be studying direct numerical simulation then i wouldnt say that Star is the best tool to be doing it with!

Hi Joel, I read in literature that for doing aero acoustic analysis LES or DNS are good. So I want to do it in STAR CD. fairly good accuracy is enough for me. I do not have any other software. If I switch over to LES model it is not running. I am using crank-nicolson and CD scheme. It give me error that you should switch it to transient, even though I did it.

Thanks in advance.

I think it is more a confusion of definitions in your case, DNS involves complete numerical simulation without the need for turbulence models by refining the grid to the smallest length scales and as such has (at the moment) no real practical usage due to the enourmous computer resources and time involved so unless you have a supercomputer and a year or two of free time you may wish to try something else!! So in your case LES may be the way to go, unfortunately i dont have any experience using LES with Star so you may wish to speak to tech support or wait till someone on here comes along who does.

read my reply to the LES question