IJSART - Volume 3 Issue 2 –FEBRUARY 2017 ISSN [ONLINE]: 2395-1052 Page | 18 www.ijsart.com New Technique for measurement of Discharge in Open channel flow Prof.Vishal B. Raskar Department of Civil Engineering JSPM’s Jayawantrao Sawant Polytechnic, Hadapsar Pune-28 Abstract- Using the traditional technique for measuring discharge in open channel flow a new technique of discharge measurement is being developed by calibration of venturiflume to facilitate discharge measurement, which will lead the work in efficient way and achieving economy and accuracy. The methodology which is being refined through preparing actual model and proposed model, by using the experimental observations analysing them and preparing graphical output. Keywords- Discharge measurement, Innovative Venturi flume, Open channel. Venturiflume. I. INTRODUCTION The evolving circumstances under which irrigation districts operate include growing demands for more accurate knowledge and accountability of flow throughout the conveyance network, along with increased needs for timely awareness when unexpected flow conditions are present. For open channel conveyance systems, critical-flow structures (flumes or weirs) offer the simplicity of a direct correlation between upstream water level and a corresponding discharge. Unfortunately, at many locations where flow measurement is desired there may be insufficient space available for operation of a critical-flow measurement structure under all flow conditions that may occur. The use of flumes in measuring open-channel flow began shortly after the turn of the century. Flumes have a limited but important use in such measurement. As with any other type of artificial control, such as weirs, flumes are built in streams whose channel characteristics are such that the natural stage-discharge relation is subject to shifting or is insensitive. Flumes are also built in small flashy streams where current meter discharge measurements are impracticable because of the rapidity of changes in stage, and where the difficulty of anticipating stream rises makes it improbable that a stream gages will arrive at the site during high-water periods. Flumes commonly utilize a contraction in channel width and a drop or a steepening of bed slope to produce critical or subcritical flow in the throat (contracted section) of the flume. The relation between depth measured at some standard cross section and discharge is thus a function only of the configuration of the flume and the relation can therefore be determined prior to installation. II. TRADITIONAL VENTURI FLUME The traditional venture flume used in current irrigation projects to measure the discharge in open channel flow. Fig 1.Traditional Venturi Flume. Where, 1- Convergent , 2- Throat, 3- Divergent, Angle of convergent = 21°, Angle of divergent = 7.6°, Width of throat = (Width of convergent/2) Length of throat = (Width of convergent/2) III. DESIGN OF VENTURI FLUME Fig 2. Venturi flume with dimensions Q= KC√ℎ Where,