PIV and Load Measurements of a Rotor in a Building Wake

This study investigated the effect of wind gusts on airflow in urban airspace and the resulting influence on a rotorcraft operating within this modified flow field. To study how buildings may alter and obstruct the flow field in city airspace, particle image velocimetry (PIV) measurements were taken in three separate planes. The PIV results showed that the flow fields were significantly shaped by the building rotation and flow speed. At the higher flow speed, the vorticity concentrations intensified, indicating that gusty conditions may significantly impact the severity of flow disturbances. Rotor loads data show that rotorcraft operating near buildings may see rapidly changing effective velocity and inflow angle at the rotor plane. The forces as a function of blade azimuth showed a leftward phase shift and reductions in peak magnitude with increasing building rotation angle. These findings suggest that as UAM and AAM operations develop further, it is significantly important to implement flight control strategies, improve predictions of local wind, and maybe design rotorcraft vehicles to be more tolerant of these unsteady environments.