Aeroelastic and Aerodynamic Tests of Wind Turbine with Various Polygonal Towers

Abstract

Traditionally, circular cross-section towers have been used as supporting systems of wind turbines, but weaknesses have become apparent with recent upsizing of wind turbines. Thus, polygonal cross-section towers have been proposed and used in Europe. In this study, the effects of polygonal cross-sections on the aeroelastic and aerodynamic characteristics of wind turbines were examined through a series of wind tunnel tests. Aeroelastic tests showed that a square cross-section tower showed instability vibrations, and polygonal cross-section towers showed limited vibrations for tower-only cases. However, for wind turbines with various polygonal cross-section towers, no instability vibrations were observed, and displacements increased proportionally to the square of mean wind speed. Furthermore, pressure measurements showed that local force coefficients changed largely depending on wind direction and azimuth angle. Local drag force coefficients decreased with increasing number of tower sides, approaching those of the tower-only case, and local lift force coefficients showed larger absolute values than those of the tower-only case. The maximum mean and fluctuating drag force and the maximum fluctuating lift coefficients at each height decreased with increasing number of tower sides.

Analysis of the Influence of Antenna Arrangement Parameters on the Aerodynamic Performance of Telecommunication Towers

“…Wind tunnel testing is a reliable method to obtain the aerodynamic characteristics of slender tower-like structures. Kim et al [1], using wind tunnel tests, found that polygonal towers have better aerodynamic stability and vibrational response than traditional circular towers. Mannini et al [2] focused their wind tunnel experimental studies on the aerodynamic loads during the pre-assembly stage of offshore wind turbine towers, discovering that the height of the tower significantly impacts aerodynamic loads.…”