Experimental Investigations into the Effect of Urban Airflow Characteristics on Urban Air Mobility Applications

Unmanned Aircraft Systems (UAS) operations in urban environment are significantly challenged by the complex airflow structures and high levels of turbulence owing to the densely built-up regions and the presence of tall buildings. This paper investigates the urban airflow characteristics that are expected to pose significant challenges to the flight of unmanned aircraft systems and impair their aerodynamic stability. Using experimental methods, a 1:400 scale city model was tested in an Atmospheric Boundary Layer (ABL) wind tunnel at various wind incidence angles to capture a representative range of wind speed changes, wind direction changes, wind shear and turbulence intensity flow features. The results can be used as a first step in informing regulations for UAS operations in urban flows, where the most severe flow conditions are those which contribute to develop operational limits. This paper reveals the severity of the flow conditions in representative urban environments, particularly around and between the buildings.