| Research Abstract |
This research project is concerned with the flow control mechanism produced by the higher-order function of the flight organs at the animal flight. The wings of the dragonfly, Pantala flavescens, the horsefly, Tabanus rufidens, the fly, Parasarcophaga crassipalpis, and the vinegar fly, Drosophila lutea were observed microscopically making use of the scanning electron microscope. The surface roughness of the insect wings was measured by a three-dimensional, optical shape measuring system. It was found that mosquito wings have scales along veins, and the length of scale is about 90 microns. With respect to the structure of the flight feather, the flight feathers of pigeon and budgerigar were examined using the small low-turbulence wind tunnel. A three dimensional motion analysis system revealed the wing motion of the flying animal. The free flight of the flying animal was analyzed. The relationship between the insect flight and its wing structure was discussed. Some experimental studies on dragonfly wings have been performed with a three-dimensional curved shape measuring system and a stereoscopic Particle Image Velocimetry (PIV) system. The three -dimensional velocity field was measured around the forewing of the dragonfly. The flow for wingtip was observed in the vicinity of the upper surface of the wing, and the flow for wing root was observed in the lower surface of the wing. A comparison between Diptera wings and flight feathers of birds was made from the point of view of functional design. It was found from the comparison that they have some similar points and difference in relation to the animal flight mechanism.
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