Hi......

I study 2D turbulent flow around bluff body. My geometry is symmetry but stream function don't show symmetrical. I want to learn cause of thise problem. may source of this case occur that the problem is 2 dimensional.

Thanks....

Actually, the stremfunction should not be "numerically" symmetric. That is, the qualitative behaviour of the contours will be, but not its values. Think for example at the 2D Poiseuille flow and check if its streamfunction is symmetric... In this case the streamfunction and the vorticity will be the two variables without symmetry

If there are also velocity variables that are not symmetric...

...in 2D bluff body simulations there could be vortex shedding so also the "qualitative" behaviour will not be symmetric. And if your grid is fine "enough" and the simulation (obviously) unsteady there could be some other effects that we can call "turbulence" (not in it's physical sense) and so your streamfunction will definitely not be symmetric.

thanks for your interest