A Non-Intrusive Sensing Technique to Infer Optimal Flow Control in Serpentine Inlets

Abstract

A non-intrusive technique to infer optimal flow control efforts from two flow affecters within serpentine inlets was developed for the purpose of active flow control. Lockheed Martin has developed a micro-jet, vortex-generator-based (VGJ) flow control technique that effectively reduces flow distortion and increases total pressure recovery in serpentine inlets using two strategically placed flow affecters. An automatic control system was deemed necessary to control and optimize the two flow control input levels corresponding to the flow conditions. The vital missing link in achieving feedback control, a non-intrusive sensor capable of assessing the flow quality at the aerodynamic interface plane (AIP), was fulfilled using wall-imbedded microphones. A wall-pressure signal was developed to accurately observe the aerodynamic metrics of circumferential total pressure distortion intensity (DPCP) and average AIP total pressure loss. This non-intrusive sensing technique was then coupled with Lockheed Martin's flow control technique in order to achieve a successful demonstration of an optimal serpentine inlet flow control system.