Kinetic Energy and Momentum Correction Coefficients for a Small Irrigation Channel

The main aim of this study was to determine the kinetic energy and momentum coefficients of a small trapezoidal irrigation canal. A laboratory setup with a cyclic flow of water was used. The flow cross section was divided into ten equal sections with nine verticals in between. Pitot static tube was used to measure static and stagnation pressure heads at 1, 2, 3, 4, 5, or 6 point on the verticals. These measurements were conducted at a depth corresponding to 0.1h, 0.2h, 0.4h, 0.6h 0.8h and 0.9h from the free surface of the water in the canal. The different between stagnation head and static head was used to compute the local instantaneous velocity at each measured point. Three different discharges ware used 3.5, 9.5, and 11.4 l/s. The results of the study reaffirms the non equal to unity of energy and momentum correction factors and that for regular canal the value of α range from 1.10 to 1.20 and β from 1.03 to 1.07. It is recommended that the energy and momentum correction factors be taken into consideration even for simple hydraulic analysis in open channel flow. Keywords-kinetic energy coefficient, momentum coefficient, open channel, Pitot static tube, dynamic head, static head, mean velocity