Study on the influence of chordwise position of bionic fish scale structure on the cavitation flow characteristics of a hydrofoil

Abstract

To enhance cavitation resistance of fluid machinery, inspired by crucian carp scales, a bionic hydrofoil physical model was established. Numerical simulations of cavitation characteristics were performed using the RNG k-ε turbulence model and ZGB cavitation model. Analyses were conducted from five aspects: cavitation volume characteristics, cavitation morphology evolution, hydrodynamic characteristics, pressure pulsation characteristics, and turbulent kinetic energy distribution, revealing the cavitation regulation mechanisms of bionic scale structures at different chordwise positions. Results show that all three bionic hydrofoils exhibit lower cavitation intensity than the prototype. Among the three investigated chordwise locations, the FH0.3 airfoil produces the largest reduction in time-averaged cavity volume, corresponding to a reduction of 35.92% relative to the prototype under the present numerical conditions, with the smallest lift coefficient fluctuation and the most stable drag coefficient variation. The pressure spectra exhibit location-dependent changes in peak frequency and amplitude. The FH0.2 and FH0.3 airfoils decrease the intensity and spatial distribution range of turbulent kinetic energy. The bionic fish-scale structure improves flow field stability around the hydrofoil, mitigates adverse effects caused by cavity extension and collapse, and thereby effectively suppresses cavitation.