Abstract
A dielectric barrier discharge plasma actuator (DBD-PA) was applied to diffusion control of jet flows issued at Reynolds numbers (based on nozzle outlet diameter) of Re = 1.0X103 and 2.0X103 from a nozzle having an outlet with a diameter of 10 mm. The detailed flow structure was documented using particle image velocimetry (PIV) and laser flow visualization. In the experiments in the present study, the jet flow was controlled using a coaxial DBD-PA, which generates an induced flow in the same direction as the jet direction. The influence of the flow induced by the DBD-PA on the main jet flow was investigated as a function of the voltage, frequency, and intermittency. Plasma was generated by applying an alternating voltage of 2-6 kV with a frequency of 4-15 kHz and intermittency frequencies of 80, 160, 240, 320 Hz. The results indicate that flow induction becomes stronger as the frequency and voltage increase. Moreover, diffusion of the kinetic momentum in the jet was promoted. The potential core length was shortened dramatically by the DBD-PA, and jet stream diffusive mixing was promoted by the collapse vortex ring at an early stage. Since the Kelvin-Helmholtz (K-H) instability was enhanced by the DBD-PA, vortex rings formed near the nozzle and underwent early collapse.
