Effects of slope ratios on wind field over two-dimensional continuous smooth ridges using large eddy simulations

Large eddy simulations (LES) were conducted to investigate the wind field over two-dimensional continuous smooth ridges with four different slope ratios ( H / L = 0.2, 0.4, 0.6, and 0.8) for a fixed spacing ratio of D / L = 3.2 and a Reynolds number of Re L = 20000, where D , H and L represent the distance of two crests, the height, and the width of a single ridge, respectively. The focus of the study is to examine how the H / L influences the mean wind velocities, turbulence intensities, power spectra, and the associated wake structures within the atmospheric boundary layer (ABL) for two interfering ridges. The results show that wind field characteristics are highly sensitive to slope variations. As H / L increases, the topographic speed-up effect intensifies over the upstream crest, and the recirculation region between the ridges expands due to flow separation. For slopes H / L ≥ 0.6, reverse flow develops on the windward side of the downstream ridge, and the speed-up effect over the downstream crest diminishes. Turbulence intensities also increase in the wake regions, with maximum fluctuating wind velocities shifting upward. These changes are attributed to stronger flow separation on the leeward sides of both the upstream and downstream ridges for steeper slopes. This study clinterfering arifies the wind field characteristics of two interfering ridges and provides new ideas and references for research in related fields.