Paddy and Water Environment

, Volume 12, Issue 1, pp 203–212

Velocity distribution and discharge calculation at a sharp-crested weir

Authors

    • Taiwan Typhoon and Flood Research Institute
  • Jihn-Sung Lai
    • Hydrotech Research Institute, National Taiwan University
  • Der-Liang Young
    • Department of Civil EngineeringNational Taiwan University
Article

DOI: 10.1007/s10333-013-0378-y

Cite this article as:
Tsung, S., Lai, J. & Young, D. Paddy Water Environ (2014) 12: 203. doi:10.1007/s10333-013-0378-y

Abstract

A sharp-crested weir in open channel is a useful device to calculate discharge via head-discharge relationship. However, water stage measurement site and discharge coefficient significantly influence discharge calculation accuracy. Therefore, this study measures and simulates velocity distribution at the weir section using 16-MHz MicroADV and FLOW-3D, respectively. The water depth and surface velocity at the weir section are selected to characterize velocity distribution using gamma probability density function. In this study, accurate discharge is calculated by velocity–area integration method based on velocity distribution derived from measured water depth and surface velocity. The main contributions of this study are to give an exact measurement site, link velocity distribution and discharge, avoid discharge coefficient influence, and improve discharge calculation accuracy.

Keywords

Sharp-crested weir Velocity distribution Surface velocity Crest Froude number

Copyright information

© Springer Japan 2013