Experimental Characterization of a Supersonic Flow Control Actuator

Computational and experimental techniques are being used to investigate the operating characteristics of a promising cavity device for high-speed flow control called the SparkJet actuator. This actuator, which produces a synthetic jet with high exhaust velocities, holds the promise of manipulating supersonic boundary layers without active mechanical components. This paper focuses on the experimental characterization of a newly-redesigned SparkJet. Numerical parametric studies of the previous design characterized the performance attributes of the device as a function of orifice size, chamber volume, and energy deposited. Current experimental efforts to assess the new mm-scale actuator design include the application of high-resolution particle image velocimetry to quantify quiescent air operation, and the use of a miniaturized thrust stand to measure SparkJet impulse bit data and to determine an optimal duty cycle. Both data sets will also be used to calibrate the computations and to determine a confidence level in the prediction capability.