Discharge Measurements in Open Channels using Compound Sharp-Crested Weirs

Abstract

Compound sharp-crested weirs have been widely used for measuring discharges in open channels accurately with a reasonable sensitivity over a wide flow range. The flow characteristic over a compound sharp-crested weir is completely different to that over a single sharp-crested weir. The most common type of compound sharp-crested weir used in irrigation canals is the combination of a rectangular notch and a 'V notch with a small notch angle. However, the continuity of flow and precision of this type of compound weirs are reported to be poor in the transition region between two sections. As an improvement, a compound sharp-crested weir composed of two triangular parts with different notch angles has been designed and experimentally validated which proved to be accurate in measuring a wide range of discharges without any discontinuity. Several methods are also proposed to estimate the flow over the double 'V notch compound sharp-crested weir and one method is experimentally validated as most suitable.

Discharge coefficient, effective head and limit head in the Kindsvater-Shen formula for small discharges measured by thin-plate weirs with a triangular notch

“…Ghodsian (2004) obtained a new relationship for the calculation of coefficient of discharge. Martínez et al (2005), Piratheepan et al (2007) and Ali et al (2015) investigated composite TPWs with a triangular notch. Ji (2007) and Ramamurthy et al (2013) experimentally investigated TPWs with several triangular notches.…”

Analýza rozsahu prozkoumanosti přepadu přes tenkostěnné přelivy s trojúhelníkovým výřezem

“…Na základě experimentálního měření a aplikace π-teorému dimenzionální analýzy vytvořil roku 2004 Ghodsian [48] nový vztah pro výpočet součinitele průtoku. Experimenty se složenými tenkostěnnými přelivy s trojúhelníkovým výřezem se roku 2005 zabýval Martínez [49], roku 2007 Piratheepan [50] a roku 2015 Ali [51]. Experimenty s tenkostěnnými přelivy s více trojúhelníkovými výřezy se v roce 2007 zabýval Ji [52] a v roce 2013 Ramamurthy [53].…”

Prototipe Sistem Pengukuran Debit Air Pada Saluran Terbuka Berbasis v-Notch Weir Dan Differential Pressure Transmitter

“…[1,6] Besar kecilnya debit proporsional dengan tinggi rendahnya muka air yang ditimbulkan dan tinggi rendahnya muka air membangkitkan tekanan hidrostatis yang proporsional pula.…”