Length for uniform flow development in a rough laboratory flume

Uniform flow is important for physical model studies because generalizing flow data is possible only if the collected data is from locations where the flow is uniform, i.e., the test section. Presented in this paper are results from a physical model study of the channel length required for uniform flow to develop in a rough open channel with fully turbulent flow (i.e., the uniform flow development length, L_unif). The objective of this study was to develop a physically meaningful and parsimonious relationship for predicting L_unif. It is concluded that L_unif is proportional to flow depth and channel width, and inversely proportional to bed material size. Also, neither Froude's nor Reynold's number is significant for predicting L_unif in a rough open channel with fully turbulent flow.