Flow patterns in a partially vegetated large channel

An analytical study for the prediction of shallow flow motions in a very large partially vegetated channel with a free surface is presented. As observed by some previous studies, at the interface between the vegetated and non-vegetated domains, the shear layer was found to possess two distinct length scales. An inner-layer thickness establishes by the array resistance and a wider outer region, which resembles a boundary layer, has a width set by the water depth and bottom friction. In this study, we shall try to reveal some other attitudinal flow patterns at the interface between the two domains. Details regarding the evolution of the shear layers, the turbulence structures and momentum exchange are presented. To validate the proposed analytical model, a large series of experiments was carried out in a very large rectangular channel with presence of partially array of vertical, rigid, circular steel cylinders. The three-dimensional flow velocity components were measured using a 3D Acoustic Doppler Velocimeter ADV.