The Present study is conducted to find out the best inlet conditions for designing process of a high-speed wind tunnel. The inlet conditions are appropriate for the cases that the real nozzle has not been calculated and downstream parts designers (such as test section and diffuser designers) need a reasonable upstream flow condition for their calculations. Inlet boundary condition of each case has been specified by User-Defined Function. The process of User-Defined Function (UDF) specification is time-consuming and is based on a try and error method. Several cases of inlet conditions have been designed and examined. The comparison of results is shown in terms of cross-sectional and axial distributions of parameters and contours of Mach number and static pressure. Finally, the 1.2 m-length Ogive curve with 0.5 degree initial angle and after that, the case of 1.2 m-length ducthave been chosen as the equivalent nozzles.

fast. Due to recognizing of the error resulted in the surface slope reduction factor, some movement in spike geometry relative to ideal conditions was raised so the effect of reduction factor will tend to zero by increasing of the design Mach number.