Flow-Induced Noise of Shedding Partial Cavitation on a Hydrofoil

Abstract

The cavitation dynamics on a NACA0015 hydrofoil can have different cavitation shedding behaviors depending upon the attack angle and flow conditions, as discussed in Arndt et al. (Instability of partial cavitation: a numerical/experimental approach, 2000) [1] and Kjeldsen et al. (J Fluids Eng 122(3):481–487, 2000) [8]. Shedding can exhibit varying shedding frequencies (Strouhal numbers) measured based on measurements of the resulting surface pressure and body forces. Moreover, the transition from one regime of shedding to another can be abrupt with changes in cavitation number. In this work, we present an analysis of the acoustic signatures measured by a hydrophone for different shedding conditions using a Morse wavelet analysis. Using measurements of the cavity dynamics based on X-ray densitometry and high-speed video observations (Ganesh et al., 31st symposium on naval hydrodynamics, ONR 2016) [6], we present an explanation for the observed acoustic behavior.