Experimental study on the interference effects of torsional aerodynamic instability in single-axis solar tracker arrays

Single-axis solar tracker arrays are prone to experiencing torsional aerodynamic instability under strong wind conditions. This study examines the interference effects of torsional aerodynamic instability in single-axis solar tracker array through aeroelastic wind tunnel experiments. The results show that large torsional oscillation in the windward first-row limit the amplitude growth in the last five rows. As the tilt angle increases, the number of rows experiencing aerodynamic instability decreases. At high tilt angles, the solar tracker array exhibits greater aerodynamic stability than the single-row solar tracker under all tested wind directions. At a wind direction angle of 60°, instability occurs only at windward first-row of windward span. As the wind direction angle increases, the critical wind speed also increases, at winds above a critical value, oscillation at the wake spans are more severe than at the windward spans; At small tilt angles, the critical wind speed is highest at 0° or −5°, and increasing the damping ratio has inconsiderable impact on aerodynamic stability. At high tilt angles, increasement of damping significantly raises the critical wind speed and reduces torsional oscillation amplitude. Based on these findings, 0° or −5° tilt angles are recommended under low damping conditions as stow angle, while high tilt angles are preferred under high damping.