ANALYSIS OF OPENCHANNEL VELOCITY （分析浅水速度）.pdf

Reprint from RIVERTECH 96 Proceedings from the1st International Conference On New/Emerging Concepts for Rivers Organized by the International Water Resources Association Held September 22-26, 1996, Chicago, Illinois, USA ANALYSIS OF OPEN-CHANNEL VELOCITY MEASUREMENTS COLLECTED WITH AN ACOUSTIC DOPPLER CURRENT PROFILER Juan A. González1 2 2 , Charles S. Melching , and Kevin A. Oberg ABSTRACT Acoustic Doppler Current Profilers (ADCP’s) are easier to apply and more rapidly collect velocity data than traditional current-meter instruments. However, flow discharge estimates in natural rivers and canals based on ADCP measurements rely on extrapolations of the measured velocity profiles into the unmeasured zones of the flow. Furthermore, the accuracy and reliability of ADCP’s have not been rigorously tested and formal protocols for discharge measurements with ADCP’s have not been developed. Therefore, a comparison of the velocity profiles measured with an ADCP with theoretical velocity distributions is necessary. The analysis of two sets of approximate two-dimensional open-channel velocity distributions collected with a fixed ADCP at the Chicago Sanitary and Ship Canal (CSSC) at Romeoville, Illinois, is presented here. These measured velocity distributions are compared with the logarithmic- and power-law velocity distributions. The shear velocity and Nikuradse’s equivalent sand roughness were estimated by fitting the data to the logarithmic law. The shear velocity and Nikuradse’s equivalent sand roughness estimated from the first and second dat