The effect of frequency excitation and cavity shape changes on the vortex ring formation of a synthetic jet actuator

Abstract

This paper provides an explanation of the effects of cavity shape and frequency excitation on the vortex formation of a synthetic jet. In order to obtain comprehensive results, this study used both computational and experimental methods. The experimental method was prepared by applying a hotwire probe on the center point of the synthetic jet orifice to obtain the Ux (average airflow velocity from membrane movement) in a low voltage signal. The data were then transferred to an analog data converter within a record speed of 10,000 data/s. The following cavity shapes were studied: half-sphere, tubes, and conical. The studied orifice diameters were 3 mm, 5 mm, and 8 mm. The simulation began by utilizing the flow rate data from the experiment, which can be put in the Computational Fluid Dynamics (CFD) simulation boundary condition. From the visual data of the flow contour from the CFD simulation it is possible to determine the vortex ring formation quality from the Synthetic Jet Actuator (SJA). Based on this result, vortex ring formation occurs at the B3, T3, T5, K3, and K5 configurations of the SJA. The synthetic jet cavity with an 8 mm orifice diameter did not produce the vortex ring.