Distortion Management in a BLI Inlet Diffuser using Synthetic-Jet Hybrid Flow Control

Flow distortion in a 5% scale model of a blended-wing-body (BWB) offset diffuser is mitigated at high subsonic speeds (up to M = 0.55) using integrated hybrid actuators comprised of tandem configurations of passive (vanes) and active (synthetic jets) flow control elements. The inlet flow of the model diffuser is conditioned to mimic the inlet flow of an airborne BWB offset diffuser by implementation of a novel boundary layer ‘fence’. It is shown that flow distortion at the engine face is reduced by each of the passive and active elements, and the reduction is even more significant when both actuation approaches are implemented concurrently over the entire range of test Mach numbers. Hybrid actuation yields overall distortion reduction of 35% at the design flow condition (M = 0.55) using a control system that is both fail safe and does not require an external air supply.