Impact of Turbulent Time Scales on Wake Recovery and Operation

Abstract Enhancing wake recovery behind wind turbines has the potential to significantly improve power production and efficiency of large farms. Rather than investigating turbine control strategies, floater motion or global turbulent quantities such as turbulence intensity, this work aims study stability through a focus on scales inflow. Using Large Eddy Simulations single turbine, sinusoidal streamwise forcing is applied inflow with constant amplitude mean flow velocity, but differing time between 80 s 140 . For all characterised by rolling-up near into periodic shedding vortex rings, an excitation frequency resulting in velocity fluctuations several times larger that at shorter (80 - 90 ) more aggressive earlier roll-up led region, faster overall improved expected output from 6R downstream onwards. An period 80s gave rise 50% increase fictive placed 14R downstream, compared scale