Siphons as furrow irrigation measurement devices

Muir, Paul John (2007) Siphons as furrow irrigation measurement devices. [USQ Project] (Unpublished)

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Abstract

The aim of this project was to develop accurate entrance and exit loss coefficients for siphons used in furrow irrigation under different upstream conditions. Accurate entrance and exit loss coefficients are required to better estimate the discharge from siphons used in furrow irrigation. Accurate discharge information leads to improved understanding on how water is used on farms. A common measure of this usage is termed water use efficiency. Research was conducted to discover the need for accurate entrance and exit loss coefficients and existing models that estimate siphon discharge. This project centres on the equation developed by Bos (1989). The equation is comprehendible except for the origin of the combined entrance and exit loss coefficient of 1.9. This value is higher than what is usually used for estimating entrance and exit losses. A channel and siphon discharge measurement device was constructed to enable testing in the controlled environment of a hydraulics laboratory. A 4m long siphon with an internal diameter of 55mm was used in this project. The variables that were tested were the velocity passing the siphon entrance and the effective head across the length of the siphon. The insufficient volume of data obtained is subject to experimental error and it is for these reasons clear conclusions regarding the aim could not be made. However, from the data gathered from this project, the velocity passing the entrance of the siphon has no effect on the entrance loss coefficient. In addition, the entrance loss coefficient generally decreases with increasing siphon discharge. The equation developed by Bos (1989) generally overestimates siphon discharge when compared to discharges obtained by the testing performed in this project. The project confirms that the use of the Blasius equation to estimate the friction factor for use in the Darcy-Weisbach equation is appropriate. Recommendations have been made in order to improve this project and other possible influential variables on siphon flow to be considered have been suggested.


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Item Type: USQ Project
Refereed: No
Item Status: Live Archive
Depositing User: epEditor USQ
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Agricultural, Civil and Environmental Engineering
Date Deposited: 21 Feb 2008 00:14
Last Modified: 21 Nov 2013 05:12
Uncontrolled Keywords: siphons; furrows; irrigation; furrow; measurement devices
Fields of Research (FOR2008): 09 Engineering > 0999 Other Engineering > 099902 Engineering Instrumentation
07 Agricultural and Veterinary Sciences > 0701 Agriculture, Land and Farm Management > 070105 Agricultural Systems Analysis and Modelling
07 Agricultural and Veterinary Sciences > 0799 Other Agricultural and Veterinary Sciences > 079901 Agricultural Hydrology (Drainage, Flooding, Irrigation, Quality, etc.)
Socio-Economic Objective (SEO2008): D Environment > 96 Environment > 9609 Land and Water Management > 960905 Farmland, Arable Cropland and Permanent Cropland Water Management
URI: http://eprints.usq.edu.au/id/eprint/3873

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