Simulation of Wind Field in a Building Complex for Evaluation of the Wind Effect Along UAS Flight Path

Abstract

With the use of Unmanned Aerial Systems (UAS) becoming more common, wind field within urban environments becomes significant, and its impact on UAS flight should be examined to ensure UAS operations can be implemented and managed safely with little to no risk of damages and injuries to the inhabitants and infrastructures. This study presents the wind field within the Biopolis building complex in Singapore from steady-state RANS simulation using OpenFOAM v1912. The wind simulation was done using various inlet wind speeds and directions based on the measurements from a weather station near the building complex. After obtaining the velocity field for the whole area, the wind effect on UAS along a given flight path was inferred from the local wind velocity magnitude and direction along the path. When the general wind heading was aligned with the flight path, the local wind and its impact on the UAS along its path had more gradual and less extreme changes than in other cases where the UAS had to fly by crossing through the wake flow of the buildings. Additionally, for flow cases with the same inlet wind direction but different reference speeds, similarity in their results was observed when the wind velocity magnitude was normalized with respect to the velocity magnitude at the inlet boundary. Contours of the wind Turbulence Kinetic Energy (TKE) from the simulation results show that the areas with higher TKE are located around buildings at the most upstream against the wind, and these areas increase in size and TKE levels with higher wind speed.