Measuring wing kinematics, flight trajectory and body attitude during forward flight and turning maneuvers in dragonflies

Abstract

Details of the kinematics of free flight are very important to understanding insect flight mechanics. Important data for aerodynamic analysis and modeling include flight trajectory, body attitude and wing kinematics for individuals flying over a diverse array of behaviors, such as hovering, climbing and turning.A number of recent studies have focused on the kinematics of hovering and forward flight, using a variety of techniques. Azuma and Watanabe (1988) changed the velocity of the wind tunnel in their measurements. Dudley and Ellington (1990) calculated angles of attack in the free forward flight of bumblebees. Willmott and Ellington (1997) employed a variable-speed wind tunnel associated with the optomotor response to investigate wing and body kinematics during free forward flight of a hawkmoth over a range of speeds from hovering to 5 m s -1 . Wakeling and Ellington (1997) filmed the free flights of dragonflies and damselflies flying over the pond in the greenhouse at the University of Cambridge. The individuals were not restrained by either tethers or wind tunnels, but were free to vary the velocity and acceleration and could perform any flight action. In their analyses of forward flight, the stroke plane was constructed based on the assumption of bilateral wing symmetry, and variations in roll, yaw and pitch angles of the body through each flapping cycle were neglected. To date no detailed information on wing orientation or shape during free flight has been acquired.All kinds of flight behaviors are important for studying the aerodynamics and the control of flight. In turning maneuvers, the wings move asymmetrically, and the change in attitude is obvious even during one flapping cycle. We have also found that dragonflies exhibit substantial chordwise deformation and changes in camber during free flight, which might be important for aerodynamic models of flight performance.To study turning maneuvers involving obvious changing of the insect attitude, the description of wing kinematics should be based on a local body-centered coordinate system, together with the body attitude and flight trajectory. We have developed a method utilizing a Projected, Comb-Fringe technique combined with the Landmarks procedure (PCFL), in which a comb-fringe pattern with high intensity and sharpness was projected onto the transparent wing of a dragonfly in free flight. Images of the wings with distorted fringes were then recorded by a high-speed camera. Based on the distorted fringe pattern and the natural landmarks on the dragonfly wings, we reconstructed wing shape and established the body-centered coordinate system. This method allowed us to derive kinematic parameters without assumptions of rigid chords or kinematic symmetry, except for the assumption of rigid leading edges. The instantaneous attitude of the body was also measured simultaneously. We measured dragonflies in two flight behaviors: forward flight and turning maneuvers, and compared the kinematics results obtained for each of them. A robust technique for determinin...

Deformable Overset Grid for Multibody Unsteady Flow Simulation

“…3) presented in Wang and Sun [37] with the hind-wing leading the forewing in a phase of 180 o . Two kinematics of the motion were simulated: one is for rigid wings; the other is for flexible wings with camber deformation according to the data measured by Wang and Zeng [38]. The scattered camber deformation data during one flapping cycle are fitted into a curve as shown in Fig.…”

Flexible Wing Kinematics of a Free-Flying Beetle (Rhinoceros Beetle Trypoxylus Dichotomus)

“…The angle of attack for a moth of species Helicoverpa armigera was reported for variation in range from 35 to 160 [12]. Wang et al [22] reported the torsion angle of a dragonfly wing but they only indicated the torsion angle in the middle wings. The beetle had larger amplitude and more significant variation in the angle of attack along the spanwise direction.…”

“…The significance of wing camber deformation was evident in a wide range of insect groups, such as dragonfly [22] , moth [12] , honeybee [34] , locust [23] , and hover fly [23] . However, the investigation of change in the camber along the spanwise direction has been limited.…”

“…Some previous studies have reported an aerodynamic advance in the camber deformation of wings. In the dragonfly, a positive camber deformation of the hind wing during a downstroke generated a vertical force, whereas a negative camber deformation of the wing during an upstroke generated a thrust force [22] . A similar pattern can be clearly observed in beetles.…”

“…Prior reseachers constructed dynamically scaled-up robotic model to observe the flow field aound flexible hawkmoth wings in hovering flight [21] . Even though camber deformation has been demostrated quantitatively in a number of insects, including dragonflies [22] , locusts [23] , hover-flies [23] , the literature lacks the necessary details regarding the wing deformation of insects in free flight.…”