Drag Reduction and Turbulent Characteristics of a Low Aspect Ratio Wing with Fluidic On-Demand Winglet 01-16-01-0003

An investigation was carried out to evaluate the potential aerodynamic benefit of spanwise jet injection from the wingtips. Aircraft currently use conventional solid winglets that add extra structural weight. However, results reveal that fluidic on-demand winglets effectively reduce drag for low-speed flight regimes without the addition of any extra weight. These utilize the spanwise airflow from the wingtips using hydraulic actuators to create jets that negate tip vortices. This research aims to investigate the fluidic winglet jet characteristics on the aerodynamic performance of the wing. Results indicate that the spanwise blowing shifts the core of the wingtip vortices upward and outward from the wing surface. In a particular range of jet velocity ratio, the magnitude of vorticity near the wingtips tends to reduce, resulting in a reduction of induced drag. Scrutiny of turbulence parameters such as turbulent kinetic energy (TKE) and turbulent dissipation rate due to fluidic winglet provided insight into the physics of the flow modulation such as diffusion of vorticity field due to jet injection. The simulation results reveal that jet injection, particularly for the regimes of jet injection velocity where significant drag reduction is achieved, and the scales of turbulence reduce close to the wing surface, highlighting that additional turbulence control measures are not required to implement fluidic winglets. The culmination of this study is that the implementation of fluidic winglets leads to a significant reduction in drag at low speeds for low aspect ratio wings.