Pulsed Plasma Jets for Active Control of Shock Wave/Boundary Layer Interactions

ABSTRACT: The performance of supersonic inlets, actuators, and scramjet isolators is limited by shock wave/boundary layer interactions (SBLIs). These interactions lead to flow separation, increased total pressure loss, and fluctuations that can cause excessive thermal or structural loading. Current control strategies to mitigate SBLI effects rely on bleeding the boundary layer upstream of the shock or enhancing the momentum transfer between the freestream and boundary layer. An ideal SBLI actuator will have low induced drag, high control authority, high frequency response, and low power requirements. Current actuators fall short in one or more of these areas. In this research program, Creare and our collaborators are developing pulsed plasma jet actuators for active SBLI flow control. This type of actuator has demonstrated the potential for all the ideal actuator traits listed above. In Phase I, we experimentally demonstrated the ability of our actuators to reduce the size of a separation bubble caused by a compression ramp SBLI. We identified the effects of actuator geometry, location, and forcing conditions. In Phase II, we will refine the design of our actuators and test them over a range of SBLI geometries and flow conditions. BENEFIT: Technology derived from this program will be in the form of new SBLI flow control actuators and actuator implementation schemes. These actuators will be beneficial on supersonic inlets, control surfaces, and scramjet isolators. They may be used to reduce flow pressure loss, separation size, and potentially damaging oscillations caused by SBLIs. They will enable optimal engine performance over a wide range of flight conditions for both supersonic and hypersonic vehicles. The high frequency response of the actuators will allow them to be used in concert with new high-bandwidth control strategies for arresting scramjet unstart. When not needed, these non-intrusive actuators may be turned off, leading to minimal induced drag.