Natures wonders: mosquito aerodynamics (Introduction)

by David Turell , Friday, March 31, 2017, 03:22 (2577 days ago) @ David Turell

They have slender wings with complex motions for lift:

https://www.sciencedaily.com/releases/2017/03/170330115241.htm

"Well known carriers of diseases, mosquitoes' abnormally long, narrow wings and distinctive flight behaviour set them apart from other insects. Not only that, but when flapped, these wings move back and forth approximately 800 times each second -- far faster than any other insect of comparable size. To compensate for these rapid movements, their stroke amplitude (the angle through which the wing sweeps) is less than half that of any other insect measured to date.

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..."revealing that mosquitoes enhance their flight forces using two novel aerodynamic mechanisms that make use of rapid and exquisitely controlled wing rotations.

"In addition to generating lift by leading-edge vortices, which are rotational, bubbles of low pressure created along the edge of the wing, mosquitos use two novel aerodynamic mechanisms to make them fly; trailing edge vortices and rotational drag. The trailing-edge vortex is a new form of 'wake capture', where the mosquitoes align their wings with the fluid flows they created during the previous wingbeat, recycling energy that would otherwise be lost to the environment.

''The usual flapping pattern of short, fast sweeps means that mosquitoes cannot rely on conventional aerodynamic mechanisms that most insects and helicopters use." says Dr Richard Bomphrey of the Royal Veterinary College, who led the study, published this week in the journal Nature. "Instead, we predicted that they must make use of clever tricks as the wings reverse their direction at the end of each half-stroke.'

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"These new aerodynamic mechanisms help explain the unusual shape of mosquito wings. 'In most insects, aerodynamic forces increase as you move out along the wing length because the wing tip travels faster than the wing root,' says Dr Toshiyuki Nakata, from Chiba, who ran the computer simulations. 'However, by exploiting aerodynamics that rely on rapid pitching of the wing, the force can be produced along the entire length. Having a long slender wing can therefore increase lift force and simultaneously reduce the cost of flight.''

Comment: With the unusual wing shape it is hard to imagine this developed stepwise. The shape and the motions all had to develop at once or the insect would not fly.. Saltation. In a way reminiscent of hummingbird flight.