Design analysis of a piezoelectrically driven synthetic jet actuator

Technological advancement is being realized by using piezoelectric synthetic jet actuators to generate managing forces and moments with zero-net-mass-flux oscillatory jets for various air flow control applications. This paper firstly explores the synthetic jet flow behavior for a dual-diaphragm piezoelectrically driven synthetic jet actuator. In the experimental study, a flow visualization system was utilized to acquire the particle streak images scattered from red fluorescent spheres for examining the synthetic jet flow. The centerline velocity of the jet was measured with a hot-wire anemometer. For exploring the formation progression of synthetic jets, the numerical analysis implemented unsteady three-dimensional conservation equations of mass and momentum with a standard k–ε two-equation turbulent model adopted for turbulence closure. The moving boundary was also treated to represent the motion of the piezo diaphragm under actuation. For a complete sinusoidal actuation cycle at an operating frequency of 648 Hz, the synthetic jet flow pattern was simulated and compared with the visualized image and measured centerline velocity distribution to validate the computer software. In general, the far-field flow structure was fairly similar to a common continuous turbulent air jet; whereas, the predicted time-recurring formation of a vortex pair was observed in the near field. The surrounding air close to the slot was also drawn into the cavity of the actuator when vortex pairs advected sufficiently downstream. Numerical experiments were then extended to assess the performance of synthetic jet actuators by systematically varying the driving voltage, relative phase delay of frequency, width of the slot and depth of the actuator cavity