Numerical Investigation of Highway Slope Topographic Effects on Wind Loads of Slope-Mounted Photovoltaic Systems

Highway slope-mounted photovoltaic (HSPV) systems are increasingly deployed along expressways, yet wind loads on panel arrays can be strongly modified by slope-induced topographic effects. This study establishes a full-scale CFD framework (ANSYS Fluent, RANS with the SST k–ω model) to quantify the evolution of roadside wind profiles over embankments and the resulting wind loads on HSPV arrays. The inlet boundary layer, mesh independence, and surface pressure distributions were validated against theoretical profiles (errors < 5%), mesh refinement, and wind-tunnel data from the literature. Seven slope geometries (H = 2–10 m, i = 1:1–1:1.75) were analyzed to characterize wind-profile deviation and recovery height, followed by simulations of a 3 × 40-module array to evaluate shape and moment coefficients. Topographic effects are concentrated in the near-ground layer from the slope toe to crest, producing toe deceleration and mid-to-upper-slope acceleration; increasing H markedly enlarges the affected height range. For arrays, the slope ratio governs wake superposition and drives strong row-wise differentiation, with the rear row consistently yielding the most unfavorable net pressure and bending moment. Steep slopes can reverse the moment sign, with the moment coefficient varying approximately from −0.15 to +0.15 across the investigated cases, whereas gentler slopes amplify positive moments in the rear rows, suggesting that design checks should prioritize rear-row modules over single-row references.