Numerical Investigation on the Cavitating Flow and the Cavitation-induced Noise in the Pump-jet Propeller

Abstract

The noise hazard posed by cavitation in pump-jet propellers is a significant concern during oceanic operations. This study evaluates the cavitation performance and associated noise characteristics of pump-jet propellers in underwater conditions, further examining the interplay between cavitation phenomena and noise radiation. Cavitation performance across varying advance coefficients was scrutinized using the k-ω SST turbulence model alongside the Zwart cavitation model. Employing Lighthill’s analogy method and bubble radiation theory, analyses of flow-induced noise and noise due to cavitation were conducted. The findings indicate an intensification of cavitation within the pump-jet with increased rotational speed and a reduction in cavitation number, aligning pressure and velocity distributions with observed cavitation patterns. Cavitation markedly elevates flow-induced noise levels, with noise under cavitation conditions found to be around 50 dB higher compared to non-cavitation conditions. Considering cavitation bubble radiation noise, the volumetric pulsations and their amplitudes in the pump-jet enlarge as the bubbles progress through initial growth to maturity. Predominantly, the noise levels from bubble volume pulsations occur within low to medium frequency ranges.

Keywords

• pump-jet propeller
• numerical simulation
• acoustic computing
• cavitation
• noise