Wind tunnel measurement dataset of turbulent flow over two-dimensional ridges and three-dimensional hills with smooth and rough surfaces.

This paper presents a high-spatiotemporal-resolution dataset of turbulent flows over two-dimensional (2D) ridges and three-dimensional (3D) hills with smooth and rough surfaces measured in a boundary-layer wind tunnel. This dataset extends the experimental measurements reported in the research article entitled "A wind tunnel study of turbulent flow over a three-dimensional steep hill" by Ishihara et al. (1999). In addition to the original 3D smooth surface case, new measurements on 2D smooth and rough ridges and a 3D rough hill are conducted to clarify the effects of surface roughness and topography on the hill-induced flow field. The three velocity components on multiple representative horizontal and vertical planes around the hilly terrains were measured under different surface roughness conditions. Mean and fluctuating velocity profiles in the wake region are presented along with details of the measurement and data acquisition procedures. This database provides methodological guidance for future wind tunnel studies over complex terrain, including probe arrangement, data acquisition, and experimental design to capture complex mountainous wind fields. Furthermore, it provides a benchmark for validating computational fluid dynamics (CFD) simulations, improving turbulence models, and assessing wind resources in mountainous regions.