IDDES simulation of the performance and wake dynamics of the wind turbines under different turbulent inflow conditions

Abstract This paper aims at investigating the effect of the inflow turbulence on the aerodynamics and the wake instabilities of the wind turbine. The improved delayed detached eddy simulation (IDDES) combined with the overset grid method is performed to model the NREL S826 airfoil wind turbine at design operating condition ( λ = 6.0 ). The mean loads of power coefficient ( C P ) and thrust coefficient ( C T ) show good agreement with existing experiments data. The normalized mean velocity U / U r e f profile and normalized turbulent kinetic energy k / U 2 r e f profile within the wake is also consistent with the experiments data, indicating a fairly accurate predictions of the wake turbulence. The detailed analysis of wake vortex structure, mean Reynold's stress distribution and PSD spectrum of turbulent kinetic energy are utilized to explore the effect of incoming turbulence on the wind turbine performance and the mechanism of the wake instability. The incoming turbulence and wind shear may promote the tip vortex instability and accelerate wake recovery, thus more attention should be paid to the design procedure and layout of wind farms.