Numerical investigation of tip vortex cavitation noise with an emphasis on environmental nucleation effect

The multiscale interactions between macroscale cavities and microscale nuclei influence the tip vortex cavitation (TVC) dynamics and its induced noise. To study the underlying mechanisms, we employ a two-way transition and coupling Euler–Lagrange model. Through acoustic analogy analysis, we identify the cavity volume fluctuations as the main vocal mechanism of cavitating tip vortex, highlighting two critical cavity dynamics, i.e., the breathing mode of surface waves and the cavity collapse of downstream end. Multiscale simulation results suggest that the merging of microscale bubbles into macroscale cavities can generate a more continuous tip vortex cavity and enlarge the cavity size. In addition, the high-frequency noise is significantly increased due to the nuclei injection, and the cavity collapse noise is reduced due to a more continuous cavity. Our investigation provides a foundation for understanding multiscale TVC dynamics and noise.