Supersonic flow past a wedge with counter flow
 

I am modeling a supersonic flow past a wedge. The problem is 2-D symmetric (thus the model represents a ramp air intake). The inlet Mach number is 3.0 and the free stream stagnation pressure is 80 psia. There is a counter flow jet positioned one cm away from the wedge exit on the symmetry plane with a counter flow stagnation pressure of 80 psia and the flow is choked (M=1). I am using density based implicit solver with Spalart Allmaras turbulence model. On iterating the residual value does not drop below 10^-2. It keeps oscillating around this value, upto 10000 iterations. However, I have converged solutions for the same problem without the counterflow. Can any one suggest me ways to resolve this non-convergence issue. Thanks ahead of time for your advice. Regards Mahesh