Passive Flow Control in Boundary Layer Ingesting Semi Submerged Inlet

Abstract

In this study, effect of vortex generators used as passive flow control devices in a boundary layer ingesting semi submerged inlet is computationally investigated with the commercially available flow solver Fluent 14.0. Studied intake duct exposed to high level of boundary layer ingestion such that ingested boundary layer thickness corresponds to the 40% of the intake throat height. Four design variables used for vortex generator sets are taken as vortex generator height relative to local boundary layer thickness, angle of incidence, number of vortex generators and the distance between separation point and the vortex generator set. Effect of each design variable on intake performance is discussed in detail. Best vortex generator set provides 80% reduction in total pressure distortion with negligible amount of reduction in total pressure recovery at the design condition. Moreover, it is shown that, passive flow control ensure sufficiently uniform flow at the engine face for not only design angle of attack but also for the whole angle of attack range encountered in flight envelope.