Abstract
The fundamental characteristics of open channel flows over a wavy bed in the upper regime are investigated theoretically by means of the perturbation method. The depth averaged momentum equation including the effect of vertical acceleration is applied to the free surface profile analysis. Using the ratio of the amplitude of the wavy bed to the normal depth as the perturbation parameter, the 2nd order solution is derived to study the relation between the friction coefficient and the non-dimensional hydraulic parameters. The theoretical results are compared with the previous experimental studies to make clear the applicability and the drawbacks of the basic equation.
