Water Flow around a Flapping Foil: Preliminary Study on the Numerical Sensitivity

In this paper we focus on the water flow around a vertical hydrofoil used to generate power in micro-hydropower-units, based on the flutter phenomenon, which leads to pitching and sway oscillations of the foil. 2D computations are performed in COMSOL Multiphysics, in unsteady turbulent flow, for one-way pitch motion of the foil, with pitch angle varying over 50 degrees. This assumption precedes further studies that will point on the dynamic pitching and sway oscillations in unsteady flow. The numerical sensitivity of the results is analyzed through a grid dependency test from coarse to very fine mesh, in order to depict the trusted values of the lift and drag forces acting on the foil. The variation of the lift and drag forces during the one-way pitch motion is obtained for the studied NACA 0015 foil.