An Investigation of Velocity Distribution in a Rough Bed Meandering Channel

Abstract

An investigation of flow and velocity distribution of a simple meandering channel with rough bed is portrayed experimentally and numerically. Experimentation of fluvial flows are actively dominated by geometric complicacy along with variation in measurable property such as velocity distribution on sectional parameters like width ratio, aspect ratio and hydraulic parameter such as relative depth. Generally rivers have a tendency to meander their flow path for minimization of energy loss throughout their way. The geometric section selected here for experimental analysis is a rough bed sine generated trapezoidal main channel except the wide flood plain circumscribed on both sides of main channel. A series of experiments were conducted in this study for the evaluation of longitudinal velocity distribution along the width and depth of the channel at different cross-sections (13 sections) along the meander path selected of a highly sinuous channel of cross-over angle 120 degree. Meander course experimented is from one bend apex to the subsequent bend apex which changes its path on the cross-over. Bend apex is just similar to a bend on a road or race circuit i.e. a function of highest curvature. Cross-over defines the part where the sinuous channel alters its sign. The study explores the varying velocity profiles from one bend apex to the other with higher velocity always remaining on the inner bank of main channel, which hence moves from one bend to another as the meander path changes its course at the crossover. The experimental results were also compared with another researcher’s work having the same geometrical parameters, with a smooth bed and different aspect ratio. As a reciprocal study to this experimental examination attempted in this work, a numerical hydrodynamic tool viz. CCHE (Centre for Computational Hydroscience and Engineering) developed by NCCHE, University of Mississippi, US is applied to simulate the inbank flow velocity distribution and validate the experimental result. The 2D and 3D version of the hydrodynamic tool mentioned above were formulated to the meandering channel for getting a statistical comparison between the experimental and numerical analysis of the velocity profile variation. vi TABL