Control of a boundary layer over a wind turbine blade using distributed passive roughness

Abstract

Wind turbines are mostly prone to reduced aerodynamic performance due to the inevitable occurrence of the roughness on blades. However, it may be possible to control the boundary layer by means of the right sort of roughness. In this study, distributed passive roughness is applied to the surface of NACA 63-415 airfoil. The influence of the roughness on the aerodynamic performance is numerically investigated by means of the TSST turbulence model for 10(3) <= Re <= 3 x 10(6) and for the angle of attack alpha = 6 & DEG;. Results show that the effect of roughness on the airfoil performance is negligible for Re <= 10(4). However, for 5 x 10(4) <= Re <= 1.5 x 10(5), the surface roughness can significantly improve the aerodynamic performance. Furthermore, for Re = 2.5 x 10(5), the roughness still has a favourable effect until the roughness height of h = 0.1 mm. Moreover, it is observed that for 2.5 x 10(5) <= Re <= 3 x 10(6), the lift to drag ratio is decreased by the application of roughness. Consequently, this study reveals that the implementation of the right sort of roughness can enhance the aerodynamic performance of the investigated wind turbine blade profile for some particular flow conditions.& nbsp;(c) 2021 Elsevier Ltd. All rights reserved.