Planform Effects for Low-Reynolds-Number Thin Wings with Positive and Reflex Cambers

To understand the planform effects on low-Reynolds-number aerodynamic characteristics for micro air vehicles, various cambered thin plate wings were studied by numerical simulations based on Reynolds-averaged Navier–Stokes solutions with transition modeling. Six wing planforms, with the same wing aspect ratio and area, a positive camber at the quarter chord location, and a reflex camber near the trailing edge for longitudinal stability were selected for the study. They include a rectangular wing, four taped wings with the same taper ratio but different leading-edge sweeps, a Zimmerman wing, and an inverse-Zimmerman wing. For validation with available wind-tunnel experimental data, an investigation of a circular wing planform with a similarly cambered profile is also presented. The results show that the Zimmerman wing planform gives the best lift-to-drag ratio at the design condition, whereas the tapered wing with higher leading-edge sweep produces higher maximum lift. Flow separation and vortical flow structures on the upper wing surface are presented to gain insight into the different aerodynamic characteristics for the different planforms.