Probing into gas leakage characteristics of ventilated supercavity through bubbly wake measurement

The stability of ventilated supercavitation is strongly influenced by gas leakage characteristics the cavity. In this study we conduct a systematic investigation such under different closure conditions including re-entrant jet (RJ), quad vortex (QV), twin (TV), and pulsating (PTV), generated from tunnel speeds ventilation conditions. Using high speed digital inline holography (DIH), all individual bubbles shed cavity are imaged downstream used to quantify instantaneous general, supercavity exhibits significant fluctuations types with rate spiking up 20 times input RJ QV closures. However, magnitude occurrence (frequency) excessive (above input) vary substantially across closures, Particularly, as transitions RJ, QV, TV, PTV increasing or decreasing speed, relative decreases sharply plateaus drops again TV PTV. Correspondingly, frequency first double peak distribution migrates single mode eventually broadened at higher These trends can be explained flow instabilities associated three mechanisms, i.e., impingement leakage, tube pulsation induced bubble pocket shed-off, whose significance changes Subsequently, two metrics introduced change needed compensate extra loss predictability respectively. Based on these metrics, suggest that operating moderate optimal for ventilation-based controls stability.