Experimental investigation on self-excited vibration and wake interference effects of flexible photovoltaic systems

Abstract

The issues of wind-induced vibration (WIV) are major technical bottlenecks in the development of cable-supported photovoltaic (CSPV) systems. In the present study, series of aeroelastic model wind tunnel tests of CSPV systems were conducted to analyze the WIV characteristics and wake interference effects. The WIV of the CSPV system is accompanied by significant structural nonlinearity, which causes the increase in mean response and vibration amplitude to gradually slow down with increasing wind speed. And it leads to a linear increase in the dominant frequency of vibration in the CSPV system as wind speed increases. The wake interference effect of single row changes with the wind speed. And the wake interference effect under negative AOA has a more pronounced periodic excitation effect on the rear row compared with positive AOA. In the five-rows CSPV array, the wake interference effects are more significant under positive AOA. The wake formed by first two rows induces significant bending-torsional coupling vibrations in the third row. And the wake formed by first three rows induces significant vertical vibrations in the rear rows. The wake interference effects under negative AOA primarily causes torsional vibration of the two rows behind the windward row. However, the wake formed by the first three rows causes almost no vibration in the rear row. Based on the analysis results, a ground anchor cable was proposed as a wind-resistant measure for the CSPV system, and its effectiveness was verified through experiments.