Computational study on wind turbine airfoils based on active control for deformable flaps

Abstract

This study numerically investigates the aerodynamic performance of Deformable trailing edge flaps (DTEFs) to reduce the fatigue and ultimate loads of wind turbine blades. A parametric design is adopted to ensure the flexible deformation of the DTEFs. Based on experimental data, a simulation of a baseline airfoil is performed with two methods: A fully coupled viscous/inviscid method employed by the XFOIL program and a Reynolds-averaged Navier–Stokes solver with a Transition SST (T-SST) turbulence model. The static and dynamic performances of DTEFs are then investigated under different flow conditions by using T-SST and maximizing its numerous advantages. Results indicate that under steady conditions, the effects of flap deflection on the integral forces and flow field structures of airfoils vary from attached flow conditions to separated conditions. The gaps between unsteady aerodynamic responses and static values are greater in attached flow and light stall conditions than in deep stall conditions. The ability of DTEFs to control the fatigue loads on wind turbine blades is verified. Specifically, DTEFs effectively alleviate the force fluctuations on blades under gust-induced swinging when wind speed measurements are considered.