Open Channel Discharge Measurement Using 0.127 Metre (5 Inch) Long-Throat Flume

Long-throat flumes are used in flow measurement by developing power curve relationship between water depth and discharge. This structure provides economical and flexible water measurement capabilities for a wide variety of open-channel flow situations. The advantage of these structures includes minimal head loss, low construction cost, adaptability to a variety of channel types, and ability to measure wide ranges of flows with custom-designed structures. A series of detailed laboratory measurements were made under steady-state flow conditions through a Long-throat flume of control section width 0.127 m (5″) as there is no data available for 5″ for any flume length. Free flow and submerged flow calibration were done within flow range 0.005 m³/s to 0.022 m³/s. The result of the calibration shows discharge within calibrated flow range. The proposed equation can determine accurately the discharge with maximum deviation of ±6% and ±8% for stilling well and gauge data respectively. Henceforth, using proposed equations Ditchrider’s table and rated graph was developed for field implementation of the flume.