Hybrid pressure integration and buffeting analysis for multi-row wind loading in an array of single-axis trackers

Abstract

Unrestrained single-axis solar trackers are uniquely flexible structures that can withstand more deflections than typical aeroelastic structures such as long-span bridges or aircraft wings. These distinctive features and the aerodynamics of multi-row arrays lead to the requirement of novel techniques for design wind loads. The present study presents a hybrid technique using two separate wind tunnel tests: (i) a pressure model at a relatively small scale, and (ii) a sectional model at a larger scale. The pressure model test is used to measure the buffeting forces acting on each row of the array and the sectional model study is used to extract the variation in aerodynamic stiffness and damping as a function of wind speed. The results of these separate studies are combined to numerically simulate the buffeting response of the tracker, which predicts significant inertial and self-excited forces. Comparisons between the proposed hybrid method and wind loads estimated using a dynamic amplification approach are performed. It is shown that at high wind speeds, the self-excited forces become significant and the peak design moments exceed those predicted using pressure data alone. The proposed methodology is expected to complement aeroelastic modeling as a convenient and efficient design tool.