problem in initializing the flow for supersonic
 

Hi, I need to know how to determine the correct initial values of flow parameters to begin the iteration in a supersonic external flow arround a plane. I tried some values for x-velocity, a certain value is help to begin the iteration and other values give an error during iteration like " deviation detedcted in amg solver : prassure correction " while using a pressure far-field boundary condition in inlet and outlet. also the error like " reversed flow" while using a pressure inlet and pressure outlet boundary conditions. where is the mistak in my setting? Can some one give me a help? thanks