Paddy and Water Environment

, Volume 12, Issue 1, pp 203–212 | Cite as

Velocity distribution and discharge calculation at a sharp-crested weir

Article

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 

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Copyright information

© Springer Japan 2013

Authors and Affiliations

  • Shun-Chung Tsung
    • 1
  • Jihn-Sung Lai
    • 2
  • Der-Liang Young
    • 3
  1. 1.Taiwan Typhoon and Flood Research InstituteTaipeiTaiwan
  2. 2.Hydrotech Research Institute, National Taiwan UniversityTaipeiTaiwan
  3. 3.Department of Civil EngineeringNational Taiwan UniversityTaipeiTaiwan

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