Physical Modeling of the Atmospheric Boundary Layer in the University of New Hampshire’s Flow Physics Facility

The atmospheric boundary layer is the lowest part of the atmosphere, and is defined by a region from the surface of the earth to approximately 500-1000m altitude in which air velocity changes from zero at the surface to the velocity of the wind at a certain altitude. The type of atmospheric boundary layer is characterized by the terrain it encounters, varying from open sea and mud flats to suburban areas and city centers with high- and low-rise buildings. The goal of this project is to generate different types of atmospheric boundary layers for scale model testing in the UNH Flow Physics Facility (FPF).The project began with the analysis of smooth wall (baseline) data previously recorded in the FPF. Several arrays of roughness elements were designed to simulate varying roughness lengths experienced by atmospheric boundary layers and tested in the FPF. The resulting velocity profiles in the boundary layer were measured using hot wire anemometry and pitot static tubes. These measured velocity profiles (mean and turbulence) and velocity spectra were compared to atmospheric boundary layers using ASCE Standards (ASCE/SEI 49-12). This application can then be used in the future for wind engineering studies, such as the structural analysis of buildings