What is the boundary conditions at the region of wall jet?. with no slipe condition I encounter with large errors.

(1). With no slip condition, you will have to solve the whole flow field including the viscous sublayer of the boundary layer. And you will need very fine mesh near the wall. (2). To get good results, sixty points in the turbulent boundary layer will be required along with a good low Reynolds number model. (3).Try to refine your mesh to see whether you can get the mesh independent solution first.