Characteristics of radiated noise from the cavitation flows around a NACA16012 twisted hydrofoil

The precision in predicting cavitation noise critically depends on the accuracy of flow field simulations. In the present work, we employ the improved delayed detached eddy simulation (IDDES), coupled with Spalart-Allmaras (SA) turbulence model and Schnerr-Sauer cavitation model, to simulate the cavitating flow around a three-dimension twisted hydrofoil. The accuracy of simulation is accessed by examining the power spectral density of pressure fluctuations and the percentage of resolved turbulent kinetic energy. The simulated cavitation behavior is compared with experimental observation in terms of shedding patterns and frequencies. The cavitation-radiated noise, computed via the porous Ffowcs-Williams and Hawkings (PFWH) method, is subsequently calculated. Strategies for setting different integral surfaces are discussed. An analysis of sound pressure and cavity evolution patterns for a typical cycle elucidates the correlation between the dynamic characteristics of the cavity and the noise properties. The simulation addresses the lack of experimental data, which poses challenges due to the need for numerous hydrophones and the elimination of tunnel wall effects. The combination of the PFWH source surface and the original FW-H source surface facilitates the investigation of various noise sources. The results indicate that the pseudo-thickness term approximates a monopole noise associated with cavity volume acceleration, the loading term resembles a dipole, and the quadrupole term can be obtained by subtracting from the total sound pressure. The sound pressure levels at the monitoring points reveal that the monopole term predominates, followed by the quadrupole term, with the dipole term registering the lowest values.