Why DDES=RANS?

aladdincham · May 25, 2011, 10:54

Hi everybody,
I meet a very strange problem . When i use my code to calculate a 2D naca0012 airfoil with DES, and i got the complex vortex systems. Using the same grid, when i simulated it by DDES, the result was same with RANS, who can give me some suggestion? THX

cfd_newbie · May 26, 2011, 01:02

Quote:

Originally Posted by aladdincham

Hi everybody,
I meet a very strange problem . When i use my code to calculate a 2D naca0012 airfoil with DES, and i got the complex vortex systems. Using the same grid, when i simulated it by DDES, the result was same with RANS, who can give me some suggestion? THX

which software did you use ?

harishg · May 26, 2011, 21:35

This is a big problem with DDES. It is very sensitive to the Initial condition and the grid you use. Spalart has mentioned this as a possible problem in DES. Try using IDDES or the other new versions of the model.

May 25, 2011, 10:54	Why DDES=RANS?	#1
aladdincham New Member Aladdin Join Date: Jan 2010 Posts: 26 Rep Power: 16	Hi everybody, I meet a very strange problem . When i use my code to calculate a 2D naca0012 airfoil with DES, and i got the complex vortex systems. Using the same grid, when i simulated it by DDES, the result was same with RANS, who can give me some suggestion? THX

May 26, 2011, 21:35		#3
harishg Senior Member N/A Join Date: Mar 2009 Posts: 189 Rep Power: 17	This is a big problem with DDES. It is very sensitive to the Initial condition and the grid you use. Spalart has mentioned this as a possible problem in DES. Try using IDDES or the other new versions of the model.