Evolution of vortex structures in an open deep cavity under pulsatile flow conditions: An experimental study

Experiments have been conducted to investigate the vortex dynamics in a deep open cavity driven by pulsatile flows. Physiological flow waveforms examined for mean Re ranging from 200 1000 and Wo of 10.2, 12.4, 17.6, with Strouhal numbers (Str, as function Wo) 0.065 0.98. Results show that two-primary-vortex system develops, similar steady flow, but it exhibits more dynamic behaviors evolves during cycle. Five stages evolution are defined: generation, traveling, merging, stretching, weakening. As increases, first three occur faster earlier cycle, allowing time top primary interact rear wall bottom develop. The opposite trend is found increases. While strength increases Re, patterns correlated Str, which proportional square inversely Re: vortices symmetric at low become distorted high Str. A critical Str exists beyond would not develop inside cavity. also suggest an increasing causes significant increase in-cavity unsteadiness compared Re. peak occurs later phase main flow. normalized mass flux ratio kinetic energy both linearly number.