Experimental Investigation of the Torsional Aeroelastic Instability of Single-Axis Solar Trackers

The torsional aerodynamic instability of single-axis solar trackers under strong wind seriously threatens the safety of solar trackers due to the occurrence of large torsional vibrations, and the corresponding mechanism is still unclear. In this study, the torque coefficient and torsional angle of a single-axis solar tracker are tested synchronously using an aeroelastic sectional model in a wind tunnel. The critical wind speed, torque coefficients, and interaction between the torsional angle and torque coefficients at different tilt angles are analyzed, and the following results can be obtained. Torsional aeroelastic instability occurs in a tilt angle range of -10° to 15°, and the critical wind speed decreases as the tilt angle increases. The standard deviation of dynamic torque coefficients is much larger than that of static torque coefficients, and torque coefficients showed a significant dominant frequency characteristic in the vibration state due to torsional vibration instead of wind load. The wind load in the windward area promotes vibration, while the wind load in the leeward area may promote vibration with the PV module tilt angle being slight and suppress vibration with the tilt angle being significant.