Investigation of pneumatic characteristics for a ventral S-shaped inlet at high incidence and low speed

The pneumatic characteristics of a ventral S-shaped inlet at high incidence and low speed were investigated experimentally.The results show that when the Mach number Mae of the flow at the exit increases,the total pressure recovery decreases,and the circular steady total pressure distortion,turbulence intensity and synthesis distortion increase.When Mae is at 0.45,the total pressure recovery coefficient,circular steady total pressure distortion coefficient,turbulence intensity and synthesis distortion coefficient are 0.881,1.292%,1.513% and 2.805% respectively.At the same time,the power spectrum magnitude of the dynamic total pressure signals has a peak value at 220 Hz,which confirms that a flow separation occurs somewhere in the duct.As compared with the experimental result under ground running,the results at high incidence and low speed have a higher total pressure recovery and although the synthesis distortion is also higher,the inlet is fit enough to the engine at high incidence and low speed.