Energy and momentum coefficients for wide compound channels

Abstract

Experiments were conducted in a straight smooth compound trapezoidal main channel flanked by two symmetrical floodplains having width ratio value ≈12. The point velocities were measured throughout the compound cross section and isovel patterns were analyzed to determine the values of kinetic energy coefficient (α) and momentum coefficient (β) under varying flow conditions of Froude no. between 0.277 to 0.444 and relative depth of between 0.11 and 0.43. The values obtained for α and β are 2.09 and 1.39 respectively, which are significantly higher than their respective values reported by previous researchers for compound cross sections of different size and shape. New relations are suggested to determine approximate values of α and β with R2 values more than 0.97. It is hoped that the present findings will provide new guidelines for design and research in trapezoidal compound channels. © 2013 WIT Press.