Numerical Investigation of Turbulence-Intensity Effects on Wind Loads and Wake Interference in Single-Axis Solar Tracker Arrays

Single-axis solar tracker arrays are commonly installed within the lower atmospheric boundary layer. Their wind loads are governed not only by the module tilt angle, row-to-row sheltering and wind-direction angle but also by the inflow turbulence intensity. To clarify the variation in PV array wind loads under different turbulent environments, large-eddy simulation (LES) was used to investigate the mean pressure coefficient, the standard deviation pressure coefficient and the flow field of a multi-row tracker array subjected to three inflow turbulence intensities. The model scale was 1:240, with a chord length C = 0.02 m, a ground clearance h = 0.0375 m and a row spacing of 0.047 m. The target turbulent inflow was generated in ANSYS Fluent using the narrowband synthesis random flow generation (NSRFG) method, and the inlet spectra, mean-velocity profile and turbulence-intensity profile were verified in an empty domain. Turbulence intensity had a limited overall effect on the mean pressure coefficient but slightly increased its chordwise non-uniformity. In contrast, it markedly increased the standard deviation of the wind pressure coefficient while making its chordwise distribution more uniform. The outer trackers showed greater non-uniformity in both the mean pressure coefficient and the standard deviation pressure coefficient than the inner trackers. Increasing the module tilt angle strengthened the sheltering effect on standard deviation wind loads. Oblique wind weakened the sheltering effect but generally produced greater mean wind loads and wind load standard deviations at the leeward-end modules. Instantaneous vorticity fields showed that a high turbulence intensity weakened periodic vortex shedding behind the modules. These results provide a basis for evaluating the combined effects of the turbulence intensity, tilt angle and wind-direction angle in the wind-resistant design of PV trackers.