Discharge prediction in partly vegetated channel flows: Adaptation of IDCM method with a curved interface and large-scale roughness elements

Abstract

This study provides new insight into how to predict flow discharges of partly vegetated channels with emergent vegetation. By adapting for the first time the Interacting Divided Channel Method (IDCM), applied with a curved interface approach and with the presence of large-scale roughness elements (not considered in previous studies), the total and zonal discharges of partly vegetated channels were predicted based on a series of experimental results in this study together with collected data from previous studies. Consideration of transverse momentum transfer in terms of apparent shear stress at curved interface plane showed better performance with IDCM than the Divided Channel Method (DCM) with both curved and classic vertical/diagonal divisions. In this study, we also proposed a series of expressions, easily applicable, to predict the zonal discharges of a partly vegetated channel.Many experiments were carried out in a physical model of a very large rectangular channel with the presence of rows of vertical, rigid, circular, and rough steel cylinders, representing emergent rigid vegetation. The rows of cylinders were partially mounted on the bottom of the channel, leaving lateral areas of free circulation near the walls. The three-dimensional components of the flow velocity were measured using a 3D Acoustic Doppler Velocimeter (ADV)-Vectrino.