Propagation of tributary dam-break flows through a channel junction

Abstract

For a channel with a constant discharge, the characteristics of the surge wave entering a junction are obtained from the classical Stoker solution, and then the effect of the junction is analysed by applying the momentum and mass conservation equations. Experimental cases involving different combinations of the tributary lake height and the main channel discharge were tested, and measurements show good agreement with the theoretical solution. The experiments showed that the initial lake height and initial velocity in the main channel influence the surge wave characteristics. The ratio between the Reynolds number in the lake and in the main channel can be used to predict time to peak and peak flow rate. Furthermore, power-law relations for surge wave height and velocity downstream of the junction were developed from the analytical solution.