Effects of Geometric Parameters on Flapping Rotary Wings at Low Reynolds Numbers

• Published in: AIAA journal 2018-04, Vol.56 (4), p.1372-1387
• Main Authors: Wang, Dou, Wu, Jianghao, Zhang, Yanlai
• Format: Article
• Language: English
• Subjects: Aerodynamic characteristics; Aerodynamic coefficients; Aerodynamic configurations; Aerodynamic forces; Aerodynamics; Angle of attack; Aspect ratio; Camber; Computational fluid dynamics; Flapping wings; Fluid dynamics; Hydrodynamics; Micro air vehicles (MAV); Military deployment; Parameters; Product development; Rotary wings; Warships; Wing design
• ISSN: 0001-1452; 1533-385X
• DOI: 10.2514/1.J055994

Flapping rotary wing is a novel aerodynamic configuration proposed in recent years for micro air vehicles. To understand the aerodynamic characteristics of this wing layout, a computational fluid dynamics method is employed to study how certain geometric parameters of the wings, such as camber of airfoil, radius of the second area moment, twist angle, and aspect ratio, affect the flow behavior, aerodynamic forces, and moments of the flapping rotary wing at various low Reynolds numbers. Although maximum camber of airfoil affects the flow around the flapping rotary wing, it influences only the rotary moment significantly. The increase in radius of the second area moment enhances the leading edge vortex near the tip and increases the mean lift coefficient. The maximum mean rotary moment coefficient was obtained when the wing planform was close to a rectangle. The change in twist angle alters the local effective angle of attack of the wing, thereby influencing the flow and aerodynamic forces. Excessive aspect ratio reduces lift efficiency, whereas the magnitude of rotary moment continuously increases with rising aspect ratio. Based on these findings, some suggestions on the flapping rotary wing design are proposed. These suggestions may be helpful for designers of flapping rotary wing.