Experimental Study of a Resonant Fence Actuator in a Turbulent Boundary Layer

An experimental study was conducted to examine the characteristics of a resonant oscillating fence actuator in a turbulent boundary layer. Experimental tests were conducted on static, transitioning, and oscillating fences at difierent heights and frequencies. As expected, the static fences produced spoiler-like efiects, but the results difiered signiflcantly from earlier studies in laminar boundary layers. Transitioning fences demonstrated that signiflcant disturbances could be created near the fence in times scales small relative to the time scale in the ∞ow. Oscillating fences also produced signiflcant disturbances to the ∞ow in the form of convecting vortices. The peak suction associated with these disturbances scaled with the fence height while the net lift produced scaled with the Strouhal number. Due to the large disturbances produced and the small power requirement, these actuators may be useful in many ∞ow control applications.