Hydroelastic analysis of surface piercing hydrofoil during initial water entry phase

Abstract

In the current paper, numerical simulations of Fluid Structure Interaction (FSI) of a SP (Surface Piercing) hydrofoil are conducted in order to study the influence of elasticity on the initial water entry ventilation. Using ANSYS multi physics solvers, two-way FSI analyses are conducted by the implicit coupling of URANS (Unsteady Reynolds Averaged Navier-Stokes) equations with a finite-element method. Numerical results are validated by the well-known rigid and elastic wedge water entry problems. Subsequently, computational results are presented for ranges of different velocity ratios (0.38, 0.64) and elasticity factor [0,4]. Similar to the Surface Piercing Propeller (SPP), performance curves of a wedge water entry are defined. The obtained similar trend of propeller and wedge performance curves in fully ventilated, transition, and partially cavitated operation modes shows that the adopted approach (2D-study) can be appropriate for future related studies. FSI simulation results indicate that structural deformation can highly affect the location of transition point and shift it toward the fully ventilated part at high Froude number and elasticity factor. The overall efficiency loss due to the increase of foil elasticity is observed, and overshoot time of the foil deformation related to the variation of Froude number and elasticity factor is evaluated.