Along-Wind Aerodynamic Damping of Wind Turbine Towers: Determination by Wind Tunnel Tests and Impact on Tower Lifetime

Abstract

As wind turbines become larger and their towers more slender, aeroelastic effects play a bigger role in the wind turbine’s dynamic behavior. This study focuses on the along-wind aerodynamic damping of wind turbine towers, which has been determined by wind tunnel experiments using the forced oscillation method according to Steckley’s approach. Reynolds number scale effects have been considered through surface roughness modifications using sand paper and a dimple pattern, which have been described in detail. The wind tunnel measurements are performed in sub-critical, critical and trans-critical flow regimes, as well as in low- and high-turbulence conditions, which allows for an accurate description of the required relative roughness and Reynolds numbers for achieving trans-critical conditions. The resulting along-wind aerodynamic damping values according to Steckley’s and Holmes’ approaches are compared, and an analytical relation between them is established. Both approaches are then used in aeroelastic multi-body-simulations of an onshore 6 MW reference wind turbine and their impact on the wind turbine lifetime is evaluated through fatigue proofs at the tower base section. Holmes’ approach seems more appropriate for the application in aeroelastic multi-body simulations. A lifetime extension for the wind turbine tower of approximately 0.4% is achieved for the reference wind turbine tower, which roughly corresponds to 1 to 2 months for 20 years of operation. An analytical expression is given for the estimation of the tower’s aerodynamic damping in parked and operating conditions.

Sand-Laden Wind Erosion Pair Experimental Analysis of Aerodynamic Performance of the Wind Turbine Blades

“…Zhao et al [13] designed the chord length and blade pitch distribution of the wind turbine and conducted wind tunnel tests on the prototype to verify the effectiveness of the design method. Fontecha et al [14] determined the aerodynamic damping of wind turbine towers by wind tunnel testing. Guo [15] designed and manufactured the icing wind tunnel experiment system.…”

Wind-Induced Response Analysis and Fatigue Reliability Study of a Steel–Concrete Composite Wind Turbine Tower

“…Pan et al [6] analyzed the dynamic characteristics of a wind turbine tower under wind loads and random blade loads. Robert et al [7] evaluated the effect of along-wind aerodynamic damping values obtained using the Stepley and Holmes methods on the lifespan of wind turbines. Chen et al [8] used FAST v7 software to compare and analyze the dynamic response of a pure steel tower and a steel-concrete composite tower under different working conditions.…”

Direct Power Control Based on Modified Sliding Mode Controller for a Variable-Speed Multi-Rotor Wind Turbine System Using PWM Strategy

“…The tremendous technological developments recorded in recent years have played a major and important role in increasing wind power and making use of one of the most exploited renewable energies in the world, especially in advanced industrialized countries [1,2]. This development has been accompanied and contributed by many research teams in different countries around the world, where numerous articles have been published in important scientific journals [3][4][5].…”