How hydrofoil leading-edge biomimetic structure affects unsteady cavitating flow:A numerical study

Cavitation is an unsteady complex turbulent flow phenomenon that increases the resistance of propellers and hydrofoils, reduces hydrodynamic efficiency, and erodes surfaces. Research into cavitation flow control can thus provide a vital theoretical basis to improve the safety, stability, and efficiency of underwater devices. The present work uses numerical simulation to study the evolution of unsteady flow fields in cavitation. The volume of fluid multiphase-flow method is used to capture the interface between different phases, the Schnerr-Sauer model is used to describe the cavitation process, and a large eddy simulation is used to calculate the turbulence process. In addition, the adaptive mesh refinement criterion is used to capture the interface between different phases and automatically encrypt the mesh to ensure a sufficiently accurate numerical calculation. Based on the excellent hydrodynamic characteristics of humpback whale flippers, we design biomimetically a NACA 63A 018 airfoil cross section by adding a bump on the leading edge of the hydrofoil. We then study how the bump affects the spatiotemporal evolution of the cavitation flow field, surface pressure pulsation, vorticity field evolution, lifting resistance, dynamic modes, turbulence characteristics, and pseudo-structure. The results show that the leading-edge bump significantly affects the cavitation flow field of the hydrofoil.