This chapter presents an experimental investigation of wind flow around building and urban-scale models using a wind tunnel. The primary focus is on the use of an open-circuit wind tunnel and hot-wire anemometry (HWA) for high-resolution measurements of instantaneous velocity components within the boundary layer. The chapter begins by introducing the operational principles, classification, and structural components of wind tunnels. Calibration procedures for velocity sensors, the design of vorticity generators, and surface roughness elements for replicating atmospheric boundary layer profiles are also detailed. A novel method is introduced for reconstructing two-dimensional velocity fields using single-axis hot-wire sensors, enabling accurate flow measurements without the complexity of multi-sensor arrays. Statistical and spectral analyses of the velocity signals are performed, and experimental results are compared with numerical simulations for validation. The findings support the development of reliable CFD validation techniques for assessing natural ventilation, pollutant dispersion, and wind-induced loads in climate-responsive building and urban design.