Abstract
In addition to the many typical failure mechanisms that afflict wind turbines, units in Taiwan are also susceptible to catastrophic failure from typhoon-induced extreme loads. A key component of the strategy to prevent such failures is a fast, accurate aerodynamic analysis tool through which a fuller understanding of aerodynamic loads acting on the units may be derived. To this end, a viscous-coupled 3D panel method is herewith proposed, which introduces a novel approach to simulating the severe flow separation so prevalent around wind turbine rotors. The validity of the current method’s results was assessed by code-to-code comparison with RANS data for a commercial 2 MW wind turbine rotor. Along the outboard and inboard regions of the rotor, pressure distributions predicted by the current method showed excellent agreement with the RANS data, while pressure data along the midspan region were slightly more conservative. The power curve predicted by the current method was also more conservative than that predicted by the RANS solver, but correlated very well with that provided by the turbine manufacturer. Taking into account the high degree of comparability with the more sophisticated RANS solver, the excellent agreement with the official data, and the considerably reduced computational expense, the author believes the proposed method could be a powerful standalone tool for the design and analysis of wind turbine blades, or could be applied to the emerging field of wind farm layout design by providing accurate body force input to actuator line rotors within full Navier-Stokes models of multi-unit wind farms.
Highlights
The Pacific island nation of Taiwan, having abundant wind energy resources, stable wind speed and direction, and shallow water depth, is listed by 4C Offshore Limited as one of the world’s best offshore wind farm locations [1]
In order to assess the validity of the current method’s results, pressure distribution data was computed at a number of radial locations and compared with Reynolds-averaged Navier-Stokes (RANS) predicted pressure data, solved in Fluent 6.2.16 via the SIMPLEC algorithm and one-equation Spalart-Allmaras turbulence model
Included for comparison are 2D pressure data computed around identical uniform flow using Xfoil viscous-coupled panel method which is very popular forairfoils airfoil in analysis, and is finding more[45], use ain2D
Summary
The Pacific island nation of Taiwan, having abundant wind energy resources, stable wind speed and direction, and shallow water depth, is listed by 4C Offshore Limited as one of the world’s best offshore wind farm locations [1]. Taiwan has duly “pledged to boost [its] offshore wind industry by investing NT$ 88 billion (US$ 2.9 billion) by 2020 and NT$ 670 billion (US$ 21.7 billion) by 2030” [2]. The island, being located in the northwestern Pacific tropical cyclone basin, is struck by an average of four typhoons per year, resulting in average annual total losses of NT$ 15 billion [3]. In August, 2015, Typhoon Soudelor alone destroyed eight wind turbines, causing “an estimated. The proposed wind farm units, in addition to the many typical failure mechanisms that afflict wind turbines in wind farms, such as exacerbated fatigue loading due to unsteady wind farm wake effects [5], will, have to withstand typhoon-induced extreme loads.
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