Abstract

Recently, Gurney Flap (GF) has been used to improve the performance of Horizontal Axis Wind Turbine (HAWT) by enhancing its lift coefficient. Compared to HAWT, the research on GF application for Vertical Axis Wind Turbine (VAWT) is very limited. Moreover, most work studied a GF geometry attached to the trailing-edge of a stationary airfoil, without considering the rotating effect experienced by VAWT. For this reason, a three-straight-bladed VAWT rotating blades with GF is studied by transient RANS simulation together with a stress-blended eddy simulation turbulence model to investigate the GF height effect and the flow characteristics near the blade trailing-edge. Results have shown that by introducing the blade rotating, an optimum GF height is found to be 3% of the blade chord, slightly higher than 2% chord in a stationary airfoil case. In addition, the presence of GF can suppress deep stall of VAWT blades, thus eliminating negative instantaneous moment coefficient and improving the turbine performance.