The application of laser speckle photography to the measurement of flow field

• Main Author: 鍾仁淵
• Other Authors: 丁勝懋
• Format: Others
• Language: zh-TW
• Published: 1990
• Online Access: http://ndltd.ncl.edu.tw/handle/29670785390906596569

碩士 === 國立成功大學 === 航空太空工程學系 === 78 === 　　Laser speckle photography has been used to the measurement of flow field since 1977. It is a nonintrusive velocity measurement technique with high accuracy and permits the qualitative and quantitative measurement of whole field at one instance. 　　In this study, the laser speckle photography is used to measure the velocity of a rectangular pipe and the result is compared with the exact solution. The purpose of the thesis is to establish the experimental technique of laser speckle photography and the ability of Young's fringe analyzing. 　　The whole plane autocorration method is used to analyze the Young's fringe. In this experiment, a microcomputer system is built up to process the the tremendous computing requirement. So that the analysis is simpler. The application of averaged technique used here can effectively elliminate the influence of speckle noise. From the examination, the speckle noise can be reduced for 10％ error.