The SONATE (AerodynamicS Of wiNd farms using A cross-scale inTEractions approach) project has been accepted for the Young Researchers program of the French national research agency (ANR). From 2025 to 2029, the aim of the SONATE project is to understand the aerodynamics, performance and losses of a wind farm at different scales and under inlet flows that correspond to realistic conditions of a real wind farm.
Understanding the collective aerodynamics of wind turbines is crucial to achieving, improving and optimising the performance and lifetime of individual wind turbines operating in wind farms. The complex physics of farm aerodynamics is known to be multi-scale, due to the non-linear interaction between the unsteady flow generated by the rotating blades and the tower, the interaction of the wakes of individual turbines placed close together, the wake generated by the farm itself, and the large scales of atmospheric turbulent flow affecting the farm sites. The wake interaction in particular significantly increases the power losses of the farm, up to 30-40% of production compared to its nominal operation. However, for practical applications, most industrial codes use simple analytical models of the wind farm wake, mostly based on the mean velocity deficit. Realistic flow conditions upstream of the farm, such as the atmospheric boundary layer, blockage and wake interaction dynamics, are not always included in these codes.
Therefore, what is crucial to achieve efficient industrial codes predicting wake farm performance, is an equivalent simplified model of the wind farm to generate the same blockages, losses and dynamic phenomena, based on realistic experiments under physical flow conditions corresponding to a full-scale wind farm. The project will focus on building representative reduced-order models from experiments, capable of predicting the performance of the wind farms with different inputs depending on the flow conditions (wind angle, turbulence, angular momentum added by the blades, etc.). A wind farm model will be designed and characterised with large-scale measurements in the environmental section of the PRISME laboratory wind tunnel. Porous discs will be used as surrogates for the wind turbine, which produces similar far-field wakes and for which the team is particularly renowned. The effect of the inflow parameters on the aerodynamics of the wind farm will be studied, focusing on the turbulence (using turbulence grids), the wind angle (by placing the farm in a wind rose) and the angular momentum generated by the blades rotation.