An experimental study on evolution of vortex structures in perforated cavity structures driven by acoustic waves

Abstract

In the present study, the vortex dynamics in three perforated cavity structures with different gap distances (l/d = 2, 4, 6) subjected to acoustic waves is investigated by particle image velocimetry (PIV) experiments. First, using a data-acquisition at 48 kHz and transfer function method, the incident acoustic waves of three perforated cavity structures at different frequency was examined. The relationship between the gap distances and the acoustic-vortex coupling phenomena was obtained. Then, PIV was carried out to obtain the flow fields and vortex evolution process in three perforated cavity resonators at specific frequency. Comparisons of different gap distances showed that the vortices generated by turbulent entrainment are confined at the corner in the small gap distances (l/d = 2, 4). For larger gap distance (l/d = 6), large-scale vortices occur due to the wall jet flow. Finally, the flow fields were analyzed by turbulent kinetic energy to obtain the dominant energy distribution and illustrate the energy conversion process.