High-Reynolds-number wind turbine blade equipped with root spoilers – Part 1: Unsteady aerodynamic analysis using URANS simulations

Abstract. A commercial wind turbine blade equipped with root spoilers is analysed using 2D URANS computational fluid dynamics (CFD) to assess the unsteady impact of passive devices. In this work, we present CFD results from a non-rotating single thick section located at end and without spoiler. Computations were performed chord-based Reynolds number Rec=3×106. The spoiler size height approximately 33 % local chord. Comparing existing literature, it least 1 order magnitude larger than well-known Gurney flaps. analysis first in steady state angle attack global aerodynamic forces, pressure distributions, flow field analysis. Analyses are then continued accounting for unsteadiness. induces an important wake behaviour linked apparition load fluctuations. Using wall distributions associated spatio-temporal organisation field, those fluctuations well characterised. Globally, terms lift gain, adding found be detrimental negative angles while high interest higher attack. Another drawback addition effects. dominant peak frequency emerging polar coefficients, when spoiler, which corresponds vortex shedding organisation.