Kelvin-Helmholtz instability governs the cavitation cloud shedding in Venturi microchannel

The paper shows visualization of cavitation inside a micro-Venturi channel. While the initial aim of the study was to establish supercavitating conditions inside a micro-Venturi, yet we found that this regime is suppressed due to the formation of a Kelvin-Helmholtz instability, which triggers a semi periodical attached cavity collapse. In depth observations using high speed imaging with visible light and X-rays revealed that this is, besides the re-entrant jet and the shock wave, a third mechanism leading to the shedding of cloud cavitation. In addition, a simple model was proposed which explains the formation of the Kelvin-Helmholtz instability in cavitating micro-Venturi and also offers explanation on why this is the dominant mechanism of cavitation cloud shedding at small scales.