Wake behavior and control: comparison of LES simulations and wind tunnel measurements

Abstract

Abstract. This paper applies a large-eddy actuator line approach to the simulation of wind turbine wakes. In addition to normal operating conditions, a specific focus of the paper is on wake manipulation, which is performed here by derating, yaw misalignment and cyclic pitching of the blades. With the purpose of clarifying the ability of LES methods to represent conditions that are relevant for wind farm control, numerical simulations are compared to experimental observations obtained in a boundary layer wind tunnel with scaled wind turbine models. Results indicate a good overall matching of simulations with experiments. Low-turbulence test cases appear to be more challenging than moderate- and high-turbulence ones due to the need for denser grids to limit numerical diffusion and accurately resolve tip-shed vortices in the near-wake region.

How realistic are the wakes of scaled wind turbine models?

“…turbines, achieving an excellent correlation with the experimental measurements in a wide range of conditions, including full and partial wake overlaps, wake deflection, static and dynamic induction control, and individual pitch control (for example, see Wang et al (2019Wang et al ( , 2020b).…”

“…Numerical results were obtained with a TUM-modified version of SOWFA (Fleming et al, 2014), more completely described in Wang et al (2018Wang et al ( , 2019. The code has been used extensively to numerically replicate wind tunnel tests conducted with G1 https://doi.org/10.5194/wes-2020-115 Preprint.…”

“…The same process of passive turbulence generation was simulated by using the LES code. The mesh was generated with ANSYS-ICEM, obtaining a structured body-conforming grid around the spires (Wang et al, 2019), while the bricks placed on the floor for the higher turbulence case were modelled by the IB method. Figure 3 shows the mean streamwise velocity distribution at the chamber cross-section 3.57 D in front of the rotor.…”

“…Table 1 reports the experimental and simulated power and thrust coefficients in the two cases, in medium TI conditions. Figure 5 reports a comparison of horizontal scans of the wake (Wang et al, 2019) for the aligned case at various downstream distances for both the medium and high TI cases. The figure shows hub-height horizontal time-average streamwise velocity (top panel) and turbulence intensity (bottom panel)…”

Large Eddy Simulation of an Onshore Wind Farm with the Actuator Line Model Including Wind Turbine’s Control below and above Rated Wind Speed

“…Despite not reaching there yet, the ALM has shown to be capable of simulating with a moderately computational cost in comparison to a FRS, the wind flow through wind turbines, and wind farms [19]. It has been used by different research groups to simulate a stand-alone or array of model wind turbines placed in a wind tunnel and wind farms (please see for example [20][21][22][23][24][25]). Its robustness with respect to numerical discretization has been assessed in [26], by comparing four codes with the same simulation cases.…”