Three-Dimensionality in Swept Wing-Gust Encounters*

Flow disturbances pose a significant risk to aerial vehicles, particularly smaller ones operating in urban areas, as they can lead to flight instability and potentially fatal accidents. Currently, the understanding of the physics behind three-dimensional gust encounters is limited since previous studies have mainly focused on transverse gusts encountered by unswept flat plates. Therefore, the objective of this study is to bridge this knowledge gap by examining encounters with transverse gusts at non-zero sideslip angles. The present experimental investigations conducted in a water towing tank facility, utilizing a transverse gust jet nozzle, revealed a lift response dependent on the square of the cosine of the sideslip angle and the gust ratio. The lift force curves collapse when employing the proposed normalization approach for sideslip angles surpassing 30 degrees. Three-dimensional particle tracking velocimetry using the Shake-The-Box approach gave more insight into the three-dimensionality of the leading edge vortex. These findings will contribute to the development of simplified low-order models and controllers essential for ensuring safe autonomous flight in the future.