Open Channel Flow Measurement of Water by Using Width Contraction

Present study was aimed to develop a discharge measuring device for irrigation and laboratory channels. Experiments were conducted on sharp edged constricted flow meters having four types of width constrictions namely 2:1, 1.5:1, 1:1 and 90o in the direction of flow. These devices were made of MS sheets and installed separately in a rectangular flume. All these four devices were tested under free and submerged flow conditions. Eight different discharges varying from 2 lit/sec to 30 lit/sec were passed through each device. In total around 500 observations of upstream and downstream depths were taken in the present work. For each discharge, free submerged and critical submergence under different flow conditions were noted and plotted. Once the upstream and downstream depths of flow over any of the device are known, the discharge can be easily calculated with the help of the curves developed for free and submerged flow conditions. The device having contraction 2:1 is the most efficient one as it allows maximum critical submergence.

Authors:

• Arun Goel
• D. V. S. Verma
• Sanjeev Sangwan

Keywords:

• Flowrate
• flowmeter
• open channels
• submergence.

References:

[1] V. T. Chow, “Open Channel Hydraulics.” McGraw Hill Book Co., New
York. 1959
[2] M. G. Bos, “Discharge Measurement Structures” Oxford and IBH
Publishing Co. New Delhi.1975.
[3] P. Ackers, Weirs and Flumes for Flow Measurement, John Wiley &
Sons, New York. 1978
[4] A. Balloffet, “Critical Flowmeter (Venturi Flumes).” Proceedings of
ASCE, Vol.81, Paper No. 743.1985.
[5] K. Subramanya “Flow in Open Channels.” Tata McGraw Hill Publishing
Co. New Delhi. 1986.
[6] G. Onur, A. Mehmet, and A. Necati, “Calculation of Mean Velocity and
Discharge using Surface Velocity in Small Streams”. J of Flow
measurement and instrumentation. Vol. 41, 115-120. 2015.
[7] R. L. Parshall, “The Improved Venturi Flume”, Transactions, ASCE, 89,
841-880, 1926.
[8] W. H. Hager, “Venturi Flume of Minimum Space Requirements”, J. of
Irrigation. & Drainage Engg., ASCE, Vol.114, No.2. May 1988.
[9] Samani Zohrab and Magallanez Henry, “Simple Flume for Flow
Measurement in Open Channels” J. of Irrigation & Drainage Engg.,
ASCE, Vol 126, No. 2. March/April 2000.
[10] A. Goel, “Study on a constricted width Flow meter”, M.Tech. Thesis
submitted to Kurukshetra University, Kurukshetra.1989
[11] A. Goel, “On a Flow meter for Discharge Measurement in Irrigation
channels”. International journal of Flow Measurement and
Instrumentation, vol. 17, Issue 5, pp 255-257, Oct Elseiver, Uk 2006.
[12] A. Goel and N. N. Pillai,” A flowmeter for rectangular irrigation field
channels”. Proceedings of Institution of Civil Engineers, Water
Mangement Vol.161, Issue WM3, pp135 to 139. 2008.
[13] S. Tyagi, “Sharp Edged constricted width Flow meters”, M.Tech. Thesis
submitted to Kurukshetra University, Kurukshetra. 1996
[14] S. Sangwan, “Experimental Study on a sharp edged constricted width
Flow meter”, M.Tech. Thesis submitted to Kurukshetra University,
Kurukshetra. 2001