Open Channel Flow Resistance

TLDR

Rouse’s 1965 review of hydraulic resistance in open channels highlighted the influence of cross‑sectional shape, boundary nonuniformity, flow unsteadiness, viscosity, and wall roughness, and noted that resistance phenomena can be explained by boundary‑layer theory. This paper extends Rouse’s work by investigating differences between momentum and energy resistances, point, cross‑sectional, and reach resistance coefficients, and compound/composite channel resistance. The authors discuss linear‑separation versus nonlinear approaches to alluvial channel resistances. The review concludes that extensive further research on the subject is required.

Abstract

In 1965, Rouse critically reviewed hydraulic resistance in open channels on the basis of fluid mechanics. He pointed out the effects of cross-sectional shape, boundary nonuniformity, and flow unsteadiness, in addition to viscosity and wall roughness that are commonly considered. This paper extends that study by discussing the differences between momentum and energy resistances, between point, cross-sectional and reach resistance coefficients, as well as compound/composite channel resistance. Certain resistance phenomena can be explained with the inner and outer laws of boundary layer theory. The issue of linear-separation approach versus nonlinear approach to alluvial channel resistances also is discussed. This review indicates the need for extensive further research on the subject.