Development and implementation of an urban wind field database for aircraft flight simulation

Surveillance applications of unmanned aerial vehicles (UAVs) within urban areas is made difficult by turbulent winds generated by buildings. A methodology is proposed by which wind data is pre-calculated using computational fluid dynamics and stored in a database. To capture the relevant wind field features a first generation database is proposed using three independent variables for single building simulations and seven independent variables for simulations of two buildings in close proximity (canyons). The current generation of the database is shown to be capable of simulating the relevant wind effects generated within small to moderately populated urban environments. A selection algorithm is described which determines if an aircraft is located within a region significantly influenced by the building turbulence, and if so, applies the wind data from the database. The flight data of a fixed wing UAV through a sample urban environment is used to illustrate the implementation of the database and the selection algorithm. Results show that building wake effects on aircraft position and control effort can be captured by the proposed methodology without the need to simulate the entire urban domain.