An unsteady RANS simulation of the performance of an oscillating hydrofoil at a high Reynolds number

The oscillating hydrofoil has been widely used in ocean engineering applications such as ships, underwater vehicles and ocean energy devices. However, Reynolds number of existing research are lower than real ocean applications.This study reports our recent numerical effort in studying a sinusoidally oscillating hydrofoil under unsteady conditions by solving the Reynolds-averaged Navier–Stokes equations. By using experimental test data, the numerical method is well validated. Three wake patterns are identified to fundamentally affect the propulsive performance of the oscillating hydrofoil. Only the wake in the reverse von Kármán vortex street pattern is found to generate thrust for purely oscillating motion. The leading-edge vortex is demonstrated todirectly influence the pressure distribution over the foil's surface but not the thrust.Furthermore, impact of 3D effect on vortex shedding on the hydrodynamic performance of the hydrofoil is presented. This study is expected to provide guidance on both academics and industries in relevant fields.