Development of Laser Scan Lighting System for Flow Visualization

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The purposes of this research are to develop a new lighting system satisfying following items and to develop a image processing algorism in order to obtain a set of quantitative data from a flow visualization technique for high speed phenomena such as a wave breaking ;1) to obtain a bright laser sheet lighting system by scanning a laser beam,2) the laser sheet is parallel and uniform,3) time lines are also recorded by pulsating the laser beam,4) spacial scale is able to record in a image, and5) the system has a good handling capacity.The development of lighting system was performed successfully. But an additional modification of system needed because of noise from a laser beam scanner. Two kinds of system were tested ; one is introducing a optical fiber to transfer a laser beam and the other is without a fiber. It was confirmed that the former system has a room to modify to make light loss small but the later system satisfy the requirement of the researchers in fluid mechanics.In developing a image processing technique, a new algorism was programmed to track tracers in a visualized image. The algorism was applied to an analysis of wave breaking and was confirmed that it gives a good result in estimating not only a flow field but also a vortisity field and two dimensional divergence.