Design and optimization of half flush-mounted s-shaped inlet

A half flush-mounted S-duct inlet with a large amount of boundary layer ingestion (δ =0.2H, H is the height of the air intake entrance section) was designed. And then, to facilitate the geometry parameterization of the diffuser, the optimization software ISIGHT and the Non-dominated Sorting Genetic Algorithm were adopted as platform and optimization algorithm, respectively. At last, the aerodynamic performance of the prototype and the optimization are compared. It shows that the total pressure recovery improves a little and the swirl distortion reduces by about 49.31%. In addition, geometry of the optimization also changes a lot. The centerline tends to be more modest at the entrance while more rapid at the exit. The cross-section area ascends slowly at the starting?segment, but increases dramatically and results in rapid static pressure increase near the exit. Total pressure recovery coefficient, circumferential total pressure distortion and swirl distortion at exit all improve in different Mach number of the incoming stream, though change?trend of these parameters with Mach number are not the same before and after optimization.