Study on Flow Structures of Free Overfall

• Main Author: 孫洪福
• Other Authors: 林呈
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/83918552590683415166

碩士 === 國立中興大學 === 土木工程研究所 === 86 === 　　The purpose of the present study is to make clear the characteristics of velocity field and shear stress inside the pool of a two - dimensional free overfall using flow visualization technique and fiber laser Doppler velovimetry (FLDV) and particle image velocimetry (PIV). The characteristics of the velocity fields of a free overfall (including the velocity profiles of the falling jet, of and near the slinding jet, and in the pool) are investigated experimentally, using a novel flow visualization technique as well as fiber laser Doppler velocimetry and particle image velocimetry. The range of Froude number for the approaching flow upstream of a drop structure is from 0.75 to 1.32. Several detailed flow structures, regarding the horizontal mean velocity distributions and the circulating vortex flow inside the pool and the change of the mean bottom shear stress along the base of a drop structure, are elucidated in the present study.