Impingging jets using StarCD

Anindya

I am trying to simulate a 2D impinging jet on a flat plate using StarCD. I am having problems with the Boundary conditions. I have a symmetry boundary condition on the left side(west) of the 2D domain. The bottom boundary (south) is wall(no-slip) and is fine too. The top boundary(north) is divided into 2 parts, I(north) and B1(north). I have D/2 as inlet boundary condition at I(north)where I specify the downward jet velocity, on the top left, adjoining the symmetry boundary,and that is ok too. I am having problems with the boundary conditions at B1(north) and B2(right). I have used pressure for both B1 and B2 and the results are not good. I have used wall for B1 and outlet for B2 and then also it does not give good results. By not getting good results, I mean that my U (radial velocity) velocity is increasing with radial distance away from the symmetry line, instead of decreasing. Due to the effect of the bottom wall, I expect that the velocity should decrease as we go further away and that is reported in literature too.

Please let me know what boundary condition might be a realistic simulation of the Boundary conditions at B1 and B2. In Reality they are both open surfaces. Or do let me know your suggestions.

Thanks

Anindya