The experimental study of aerodynamic characteristics with wing flexibility for hawkmoth-like wings in hovering flight

Yeonggyun Ryu

doi:10.32920/ryerson.14649267.v1

Abstract

An experimental study on flapping wing flexibility in hovering flight has been conducted to investigate the wing flexibility for insect-inspired flapping Micro Aerial Vehicles (MAVs). Hawkmoth-like wing models, derived from Manduca sexta, were made of Polycarbonate (PC) sheet with a spanwise length of 200 mm and an aspect ratio of 6.18. For the distributions of wing flexibility, the wing thickness was selected as the design variable: rigid wing (3 mm-thick) and flexible wings (2, 1, 0.8, 0.5, 0.35, 0.2, and 0.1 mm-thick). In the experiment, the wing models were constrained to the symmetrical and sinusoidal flapping motions with sweeping and rotating amplitudes of 120° and 90° in water tank with size of 3.5 m×1.0 m×1.1 m. Aerodynamic force and flow structures for flapping the wing were measured using a six-axis force/torque sensor and a high speed camera with a laser using Digital Particle Image Velocimetry (DPIV). To compare the flow structures of flexible wings with rigid wing, they were captured at the same chordwise cross-section as the rigid wing, 50% of wing length. Based on the experimental results, vortices and aerodynamic force. Consequently, the wing with thickness of 0.8 mm has better aerodynamic characteristics than other wings in hovering flight. This finding will be instrumental in identifying the range of wing flexibilities that improves the aerodynamic efficiency for the development of insect-inspired flapping MAVs.

Highlights

1.1 Motivation to study insect-inspired flapping air vehicles In past decades, much research has been conducted on the flapping flight, like the concept of Leonardo da Vinci, in nature with aerodynamics study
To compare the flow structures of flexible wings with rigid wing, they were captured at the same chordwise cross-section as the rigid wing, 50% of wing length
The delayed time influences the generation of aerodynamic force, and it appears to cause the decline of aerodynamic force

Summary

Introduction

1.1 Motivation to study insect-inspired flapping air vehicles In past decades, much research has been conducted on the flapping flight, like the concept of Leonardo da Vinci, in nature with aerodynamics study. The SR-71 flies at Mach 3 (~2000 mph) and covers about 32 body lengths per second while a common pigeon, one of natural flight creatures, covers to 75 body lengths per second at 50 mph speed [2] It shows that the biological flyers are more maneuverable than conventional aerial vehicles. The biological flyers need to investigate unsteady aerodynamics, flapping motions, flexible wings, as well as a rapid adaptation on different environment conditions [2] With these biological features, high performances in free flights can be obtained

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Conclusion