Active Control of a Pod Wake-Mid-Scale Application

Pods and externally carried stores can generate unsteady flows in their wakes with high acoustic loads capable of damaging aircraft structure. Active flow control technology has the potential to modify unsteady shedding in the wake of the pod, thereby reducing acoustic loads. In this work, an active flow control system was developed and tested on a generic pod configuration. Using open loop flow control actuation, the frequency of the acoustic loads can be modified and their amplitude reduced. In addition, wake location can also be manipulated by the active control system. A larger scale wind tunnel test on an eighth inch diameter pod with synthetic jet flow control actuators was conducted with the flow field being defined with and without the actuators operating. It was tested up to a Mach number of 0.5. Synthetic jet exit velocities in excess of 800 feet per second were achieved. As was the case for previous smaller scale pod wake control, the frequency of shedding was controlled, the location of the wake also was controlled, and the amplitude of the pressure fluctuations was reduced. Data were obtained for various actuator frequencies, amplitudes, and ejection locations on the aft end of the pod.