Author(s): Caian Huang; Xiaodong Zhao; Jiren Zhou
Linked Author(s): Caian Huang
Keywords: Hydraulic geometry; Alluvial channel; Sediment transport; Maximum entropy; Width-depth relation
Abstract: The exponent in basic hydraulic geometry relation (i. e., bj/h=ζ) is discussed in this paper. For alluvial channel, the exponent usually take a fixed value at existing width-depth relations, for example, j=2/3 (Cao, 1996), and j=0. 69 (Deng and Zhang, 1994). While for threshold channel, the exponent is unity, i. e., j=1 (USBR, 1951). So, the exponent should vary with flow intensity or sediment transport intensity. From the resistance equation and sediment transport equation, the principle of maximum entropy is used to explore how the discharge Q of regime channel adjusts impartially on its way concerning the variation of width and depth. The basic hydraulic geometry relation is derived, and its exponent is not a constant, but change with flow intensity. The exponent vary between 0. 5~1. 0, so this basic hydraulic geometry relation not only can summary the existing results, but also can unify the hydraulic geometry relation in static threshold channel and in dynamic alluvial channel.
Year: 2013