A Universal Distribution of Local Mean Velocities in Boundary Layers Flowing Over Vegetated Bottoms

In this paper a methodology is proposed to obtain non-dimensional distributions of the local mean velocity in an equilibrium boundary layer over a rigid submerged vegetation. The obtained non dimensional distributions are independent of the considered test sections and hydrodynamic conditions and are linked to the macroscopic characteristics of the boundary layer itself. The methodology is applied to local mean velocity distributions experimentally obtained in the layer of the current which flows over the vegetation. Vegetation has been modelled through brass cylinder sticks and a synthetic grass carpet. Velocities have been measured through an LDA system in different test sections and hydrodynamic conditions. Therefore, the results show the presence of a universal velocity distribution law, valid for an equilibrium boundary layer outside of the vegetated bottom, likewise already obtained in literature for uniform flows.