Aerodynamic Mitigation Measure for Wind-Induced Vibration of a Cable-Supported Photovoltaic Farm

Photovoltaic (PV) power generation has been investigated increasingly in recent years for addressing the global energy crisis. To satisfy the demands of construction on complex sites, a cable-suspended PV structure is proposed and has garnered attention for commercialization owing to its large span and favorable site adaptability. However, such flexible structures are vulnerable to wind loads. Large wind-induced vibrations (WIVs) and module failures have been reported frequently during strong winds. Most previous attempts at vibration control entail enhancing the support structure (e.g., setting inter-row rods and stable cables) or installing additional dampers, which may increase the construction cost and affect the competitiveness of solar farms. In addition to constructing a stronger support structure, optimizing the aerodynamic force exerting on PV modules is a feasible method for reducing vibrations; however, this approach has not been investigated sufficiently. Therefore, an innovative aerodynamic method involving a spoiler is proposed to mitigate the excessive vibration of a cable-supported PV array under wind action. An aeroelastic wind-tunnel test is conducted on PV arrays with and without spoilers. The WIV characteristics of the PV array are demonstrated, and the effects of the length, tilt angle, and spacing of the spoilers on WIV mitigation are investigated. Regarding the WIV control effects of multiple wind directions and PV rows, an assessment method for determining the optimal spoiler is presented based on a multiple linear regression model. The aerodynamic mitigation mechanism of the spoilers is explained based on numerical simulation. The results show that a large WIV is likely to occur in the windward midspan PV module. Setting a spoiler with a large tilt angle and small spacing is conducive to the WIV suppression of a cable-supported flexible PV farm, whereas increasing the tilt angle can, in general, improve WIV performance. The presence of a spoiler changes the flow-separation pattern and vortex formation on the upper and lower surfaces of the windward PV row, thereby affecting the total wind loads exerting on the wind-susceptible modules. Among the spoiler cases investigated, that with a tilt angle of 30°, a spacing of 1.3 times the row spacing, and a length of four times the PV-module height offers the best vibration control efficiency.