Effects of Boundary-Layer Bleed Slots on a Sidewall Compression Inlet

In this study, a 60° multi-slot configuration is implemented on the sidewall to investigate the effects of sidewall bleeds on the inlet performance and sidewall boundary layer. Numerical simulations are conducted on a mixed-compression inlet at a design Mach number of 3. To resolve the inlet startup problem, the bleed boundary condition, which considers the effects of local flow expansion, is applied to the ramp and cowl surfaces. Inlet performances, such as mass flow ratio, total pressure recovery, and total pressure distortion, are examined under various backpressure values. The sidewall bleeds effectively suppress the separation of the sidewall boundary layer and corner vortex that reduces the effective area. These effects stabilize the terminal shock structure and improve the backpressure capability of the inlet. The effects of sideslip angle on sidewall bleeds are also investigated based on the differences in the bleed mass flow rate of both sidewall bleeds and shock structure around each bleed slot corner. Furthermore, the feature of inlet performance with respect to the sideslip angle is discussed in detail.