Leading and Trailing Edge Effects on the Aerodynamic Performance of Compliant Aerofoils

Abstract

The geometry of the rigid leading and trailing edges that hold the membrane could affect the aeromechanic performance of membrane wings. In this study the interaction between the supports and a membrane aerofoil is explored. Tests are performed at low Reynolds numbers, Re = 9×10 4 , and incidences of 2 • -22• . Four different leading and trailing edge geometries have been analysed focusing on the unsteady characteristics of the wake and the structural vibration of the membrane. Results indicate that the wake's shedding frequency is dependent on membrane's support geometry for low angles of attack (α), but is independent for higher values of α. Moreover, it has been found that the aeroelastic coupling between vortex shedding and membrane vibration interact, exciting the natural frequency modes of the membrane support. Hence, the results suggest that the leading and trailing edge geometry plays a crucial role on the overall performance of the membrane aerofoil.

Development and experiments of a bio-inspired robot with multi-mode in aerial and terrestrial locomotion

“…In addition, while gliding, the compliant membrane forms a curve due to aerodynamic loading. The curve delays the angle at which the stall occurs and increases the lift to drag ratio (L/D) at high AoA and maximum lift C L and drag C D coefficients [12,22]. After landing, Pteromyini contracts its membrane to prevent sagging of the membrane while walking [19].…”

“…where ρ is the density of the fluid, v is the free stream velocity, c is the chord length, and σ is the surface tension, which is defined as σ = Et , where E is Young's modulus of the membrane and t is the membrane thickness. Arbos-Torrent [22] distinguished between a rigid composite plate and a compliant membrane using their Weber numbers. A higher Weber number correlates with more flexibility of the material.…”

“…A higher Weber number correlates with more flexibility of the material. The Weber number for a compliant membrane was roughly 10 −5 with a Reynold number of 9 × 10 4 , 200 µm of thickness and a constant chord length in [22]. Under the same conditions, a Weber number for the rigid composite plate was roughly 10 printed and assembled with the membrane using an adhesive (redrawn from [20] with permission of IEEE Xplore).…”

On the acoustic emission characteristics of airfoils with different trailing edge configurations

“…Torrent et al 15 experimentally investigated the wake characteristics and structural vibration of the membrane having four different leading/trailing edge profiles for various angles of attack (i.e., 2° to 22°) at a fixed Reynolds number of 9 × 10 4 . It was noticed that the frequency of shedding is dependent on the membrane’s support geometry at low angles of attack while it is independent for higher angles of attack.…”