Aerostructural Perspective on Winglets

作者：Khosravi Shahriar; Zingg David W

来源：Journal of Aircraft, 2017, 54(3): 1121-1138.

DOI：10.2514/1.C033914

This paper presents an aerostructural perspective on the potential benefits of wingletted wings in comparison to planar wings of the same projected span. There is no consensus in the current literature on the efficiency gains possible from winglets. The present paper takes a step further toward understanding the tradeoffs in the design of wingletted wings using high-fidelity numerical optimization based on both purely aerodynamic and fully coupled aerostructural analysis. The high-fidelity analysis in both cases uses the Euler equations to model the flow along with a friction drag estimate based on the surface area. Three configurations are considered: winglet-up, winglet-down, and planar. The results show that downward winglets produce a greater drag reduction than upward winglets for two reasons. First, the downward winglet moves the tip vortex further away from the wing from a purely aerodynamic standpoint. Second, the winglet-down configuration has a higher projected span at the deflected state due to the structural deflections. This indicates that fully coupled high-fidelity aerostructural optimization is required to quantify the benefits of winglets properly. The winglet-down configuration can reduce the total drag by up to 2% at the same weight as the optimal planar counterpart.

• 出版日期2017-5