Author(s): Yang Yang
Linked Author(s):
Keywords: Stepped channel; Flash flood propagation; Unsteady open channel flow; Energy dissipation; Flow resistance
Abstract: In the mountainous regions, flood waves resulting from frequent flash floods have been responsible for numerous damage and losses of life. In the present study, experiments were conducted to investigate surging waters down a dry, stepped channel, which was 2.4m long, 0.5m wide and with a slope of 0.133, for the cases of being roughed and non-roughed. Experimental data from the non-roughed series compared with Chanson's (2004) showed, for some smaller initial flow rate, the dimensionless wave front celerity would reduce as the flow rate decreased. For roughed series, it showed the large bed roughness had greatly consumed the energy of the flow and hence, delayed the flash flood propagation. Finally. an empirical expression of Darcy friction factor f considering both the distribution of the relative step height h* and the relative grain diameter D* was derived.
Year: 2011