Evaluation of urban wind effects on flight path planning of delivery drones using computational fluid dynamics simulations

Over the past decade, drone delivery systems have emerged as an alternative to traditional ground transportation. However, their safety and efficiency in urban wind environments remain inadequately studied. This study investigates how urban wind fields influence the safety and energy consumption (EC) of drones navigating established routes in low-altitude urban airspace. Using computational fluid dynamics simulations, urban wind environments across 12 directions and 5 force scales are obtained to assess their impact on drone operations. Results reveal that existing routes are only safe under wind speeds below 7 m/s, despite drones being rated for tolerance up to 12 m/s. Moreover, trajectory deviations are observed when drones navigate with ground speeds greater than 10 m/s. Two energy consumption (EC) indices are introduced: ψc under constant wind conditions and ψs considering statistical wind conditions. Analysis of ψc demonstrates that EC during a single flight can vary significantly with the wind conditions and drone orientation with reductions of up to 51.26% or increases of up to 203.68%. In contrast, ψs, which integrates data of the prevailing wind directions, reveals that most preplanned routes experience increases of EC up to 70% under moderate wind conditions, regardless of drone orientations. These findings underscore the critical importance of incorporating wind data into drone path planning for effective low-altitude airspace management. Ignoring urban wind effects compromises both operational safety and efficiency, potentially increasing energy costs. Finally, a framework is established to evaluate safety and EC for specific routes in urban wind environments.