Understanding the rotor wake flow characteristics of a helicopter is fundamental to the investigation of its aerodynamic characteristics. When operating close to the ground the rotor wake can reflect to create large, doughnut-shaped vortices around the helicopter. In certain environments these vortices can cause the formation of dust clouds, resulting in a phenomenon commonly referred to as brownout. This study seeks to assess the interactional aerodynamics between a small-scale rotor wake and a range of active and passive flow deflectors. Two sets of experimental results will be presented, the first a smoke flow visualisation which qualitatively assessed the potential of both passive and active deflectors to modify major wake structures. The second experiment used Particle Image Velocimetry (PIV) to assess the effect of the active deflectors.
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