Tilted wind turbines in farm configuration for improved global efficiency

Abstract

The advance in wind turbine technology has led to a tendency to gather the turbines into wind farms to benefit from economies of scale. However, the farm configuration often leads to a drastic power loss due to the interactions between the turbines. To mitigate this issue, the turbines are typically misaligned with the dominant wind direction to deviate their wake. In this paper, a tilt-induced wake deviation strategy is studied in a farm configuration using large eddy simulation of an atmospheric boundary layer and an actuator line model for the blade. The results show an effective wake deviation and a significant increase of the total power production of the farm. The evolution of the time-averaged and unsteady loads is also assessed in the wind farm, and the resulting damage equivalent load is shown to be reasonably modified when the turbines are tilted. The tilted configuration is also compared with a wind farm with yawed turbines and is found to lead to a larger power output for a reduced damage equivalent load.

Large-Eddy Simulation of airborne wind energy systems wakes

“…This effect was also reported by Haas in [17]. Similarly to tilted wind turbines, the wakes are redirected downward [18]. In addition, the upper part of the wake is more deflected than the lower part.…”

“…Examining the normal force distribution, we obtain dF n /dθ < 0 at the 0 position and dF n /dθ > 0 at π, which might play a role in the difference in the velocity deficit. This is similar to tilted horizontal axis wind turbines where a velocity deficit difference between the upper and lower part of the rotor is also observed [18]. The wake is also influenced by the tip vortices.…”

An aeroelastic coupling of an actuator sector model with OpenFAST in atmospheric flows

“…7 where a great difference is seen in the outer part of the blade. The smaller difference in the inner part of the blade is deemed to be a result of changing the location where the tip vortices are released due to the flapwise deflection [23].…”

Impact of rotor size on the aeroelastic behavior of large turbines: a LES study using flexible actuator lines

“…The ALM is used to compute the aerodynamic loads and to model the effect of the blades on the flow [13]. An advanced version of the ALM is used, as described in [14,15]: its particularity is to use a 2D Gaussian kernel for the velocity sampling and the forces distribution, which provides a better estimation of the aerodynamic forces near the blade tip, compared to using classical 3D Gaussian kernels [16,17]. No additional near tip correction method is used in the presented simulations.…”