... hawkmoth hovering leading-edge vortex (LEV) near-field flow unsteady aerodynamics Flapping-flying insects employ unsteady aerodynamic mechanisms to keep them afloat, and there have been many studies on this topic( Ellington, 1984a ; Ellington, 1984b ; Ellington, 1984c ; Ellington, 1984d...

... unsteady lift and thrust forces are validated with experimental results and are in excellent agreement. The unsteady aerodynamic origin of the time-varying yaw moment is identified. The differences in the kinematics between the right and the left wings show that subtle change in the stroke angle...

... forward flight unsteady aerodynamics forewing-hindwing interaction Navier-Stokes simulation Scientists have always been fascinated by the flight of dragonflies. Analysis based on quasi-steady aerodynamic theory has shown that the vertical force required for weight support is much greater than...

... particle image velocimetry PIV unsteady aerodynamics flapping flight micro air vehicle A quantitative description of the flow field around insect wings is fundamental to understanding the aerodynamics of insect flight. The high performance of flying insects implies aerodynamic forces larger...

... body angle and flight speed in free-flying Drosophila. Physiol. Ent. 3 , 191 -195. Dickinson, M. H. ( 1994 ). The effects of wing rotation on unsteady aerodynamic performance at low Reynolds numbers. J. Exp. Biol. 192 , 179 -206. Dickinson, M. H. ( 1996 ). Unsteady mechanisms of force...

...Adrian L. R. Thomas; Graham K. Taylor; Robert B. Srygley; Robert L. Nudds; Richard J. Bomphrey SUMMARY Here we show, by qualitative free- and tethered-flight flow visualization,that dragonflies fly by using unsteady aerodynamic mechanisms to generate high-lift, leading-edge vortices. In normal free...

... hovering unsteady aerodynamics If one applies this procedure to the case of symmetric stroke( Fig. 2A ), the downstroke has a net coefficient of √1.61 2 +1.07 2 =1.98. The stroke plane should be tilted by approximately tan -1 (1.61/1.07)≈56°, so the net force points upward. Since the upstroke...

... ) 8 3 2004 © The Company of Biologists Limited 2004 2004 dragonfly Aeschna juncea hovering flight unsteady aerodynamics power requirements Navier–Stokes simulation Dragonflies are capable of long-time hovering, fast forward flight and quick manoeuvres. Scientists have...

...Jiang Hao Wu; Mao Sun SUMMARY The unsteady aerodynamic forces of a model fruit fly wing in flapping motion were investigated by numerically solving the Navier–Stokes equations. The flapping motion consisted of translation and rotation [the translation velocity ( u t ) varied according to the simple...

... and pressure fields, from which the vorticity wake structure and the unsteady aerodynamic forces and torques were obtained (the inertial torques due to the acceleration of the wing-mass were computed analytically). From the flow-structure and force information, insights were gained into the unsteady...

... of kinematic variation and to investigate locomotor control in freely moving animals. (e-mail: walker@usm.maine.edu ) 16 9 2002 © The Company of Biologists Limited 2002 2002 unsteady aerodynamics rotational circulation delayed stall Magnus effect attached vortex lift hovering...

... the unsteady aerodynamic forces and moments were obtained. The inertial torques due to the acceleration of the wing mass were computed analytically. On the basis of the aerodynamic forces and moments and the inertial torques, the lift and power requirements for hovering flight were obtained. For the fruit fly...

...Sanjay P. Sane; Michael H. Dickinson SUMMARY We used a dynamically scaled mechanical model of the fruit fly Drosophila melanogaster to study how changes in wing kinematics influence the production of unsteady aerodynamic forces in insect flight. We examined 191 separate sets of kinematic patterns...

... methods, highlighting their respective limitations as well as strengths. The main advantages of an unsteady aerodynamic panel method are then introduced and illustrated by modelling the flapping wings of a tethered sphingid moth and comparing the results with those generated using a quasi-steady method...

... 1994 insect flight wings unsteady aerodynamics Drosophila Unlike the lift-generating surfaces of planes and helicopters, the wings of animals must frequently change direction. The wing motion of many animals consists of alternating upstrokes and downstrokes, each with an appropriate...

... amplitude. Our results seem to correspond to a new theory about unsteady aerodynamics of oscillating aerofoils. We sometimes observed variations in lagging. The forewing downstroke was delayed by 0–8ms following the hindwing downstroke. Relative lift was positively correlated to this delay. * To whom...