A HYBRID FREE WAKE SIMULATION COMPARISON OF TURBINE WAKE STEERING WITH INNOVATIVE TURBINE DESIGNS

Wake shielding in wind farms caused by the interaction of upstream energy-depleted wakes and down-stream turbines substantially reduces individual turbine efficiency and overall wind farm performance. A method is studied to alleviate this problem using shaft tilting to steer wakes upward and reduce the interaction with downstream turbines. Simulations have been conducted to verify this method and to assess its effectiveness. These simulations employ a specially developed hybrid free wake method that combines a Constant Circulation Contour Model, suitable for downwind far-wake evolution, with a Vortex Lattice Method, leading to accurate blade air-loads calculation, including unsteady effects, stall, and reduced complexity. The interaction of two inline tipped axis turbines has been analyzed to assess the advantages and challenges of wake steering in a system of turbines. Beyond the traditional HAWT, two unconventional turbine configurations have been studied with the intent to further increase wake ascent.