Variable-Frequency Fluidic Oscillator Driven by Piezoelectric Devices

A new actuator for aerodynamic flow control applications is described and evaluated in this paper: the piezo-fluidic oscillator. This actuator is a fluidic device based on wall attachment of a fluid jet and modulated by piezoelectric devices. The piezo-fluidic oscillator successfully decouples the operating frequency from the flow characteristics of the device. The frequency is specified by an input electrical signal that is independent of pressure, making this actuator ideal for closed-loop flow control applications. The oscillator exhibits high bandwidth (up to 1.2 kHz), modulation rates up to 100%, and a velocity range reaching sonic conditions. Furthermore, the bistable actuator may be operated in a steady state, with momentum flux in one of two desired directions for flow vectoring purposes. The piezo-fluidic oscillator may be used in flow control applications in which synthetic jets or plasma actuators cannot provide enough momentum for control authority. This paper details the design and characterization of the piezo-fluidic oscillator. The dynamic response characteristics are evaluated with flow visualization and hot-film probe measurements on the output.