Using single buildings and building canyons as the basis from which entire urban environments can be constructed, the wind around these simple structures can be simulated using computational fluid dynamics (CFD) and stored in a database. These basic building block elements and their associated windfields can then be assembled to represent an entire urban area. A selection algorithm is used to determine if the flow at the aircraft’s location is within the wake of a particular element’s wake and if so, the database wind is applied to the aircraft dynamics.
Shown is a simulation of the windfield generated between two buildings which form a canyon, where the background wind is flowing from right to left creating a turbulent region through which a small UAV is flown. The rapidly changing wind magnitude and direction causes the aircraft heading to change abruptly, which in turn causes the aircraft itself to move laterally. The effects can be significant for small aircraft, where the deviation in the horizontal direction as compared to a case where the turbulent wind effects are neglected is also shown.