Experimental investigation of the formation of secondary flow structures and interactions of a finite-span synthetic jet in a cross-flow at chord-based Reynolds numbers between 50,000 and 400,000 and angles of attack from 00 to 200.
Attractive to aircraft designers are compact inlets, which implement curved flow paths to the compressor face. These curved flow paths could be employed for multiple reasons. One of which is to connect the air intake to the engine embedded in the aircraft body. Secondly, they allow for tightly packed, lightweight, and low volume propulsion system designs. Therefore, a compromise must be made between the compactness of the inlet and its aerodynamic performance. Currently, the length of the propulsion system is constraining the overall size of Unmanned Air Vehicles (UAVs). Thus, more efficient aircrafts could be realized if the propulsion system could be shortened. In order to suppress flow separation regions, passive or active flow control strategies can be employed.
Micro air vehicles (MAV) are a major focus of aerodynamics today with many military as well as civilian applications. MAV flight is dominated by the unsteady characteristics of low Reynolds number flows. In this work an Electro-Active Polymer (EAP) actuator was examined as a feasible flow control actuator with application to low Reynolds number flows. The actuation of the EAP was found to be very effective in altering the boundary layer as well as mitigating laminar separation bubbles.
Passive (vortex generator) and active (a pair of synthetic jets) devices have been used in unison to create a Hybrid “fail-safe” device, which proved to be more effective than either device on its own and is the focus of this study.
The effectiveness of a finite span synthetic jet oriented parallel to the freestream direction, actuated on a finite span cylinder of low aspect ration and issuing normal to the cylinder surface was investigated experimentally using stereoscopic particle image velocimetry (SPIV), surface pressure measurements, and hotwire anemometry.
The inlet to an aircraft propulsion system is typically designed to supply flow to the compressor with minimal pressure loss, distortion, or unsteadiness.