A coupled approach to investigate the entropy parameter dynamics in open-channel flow with submerged flexible vegetation

Abstract

Submerged flexible vegetation modifies the open-channel dynamics by altering the hydrological and ecological characteristics. The velocity profiles at the top and bottom of the vegetation layer indicate the stochastic nature of the flow and hydraulic parameters. The randomness in the velocity profile at different degrees of submergence and vegetation density is explicitly represented by the channel entropy parameter. This study proposes a novel entropy-based vertical velocity distribution model by linking the 2D shallow-water model (SWM) with Shanon’s entropy theory. The convergence of the coupled model at different $\frac{\text{flow depth}}{\text{vegetation height}}$ is investigated by comparing the computed model results with the mixing length model and the published experimental data. Results indicate that the predicted velocity profiles from the entropy model agree with the experimental results than the mixing length model. Although the channel entropy parameter (M) is invariant with the flood dynamics, the submerged vegetation influences the drag force and modifies the flow-entropy nexus. The relationship between the vegetation densities and the channel entropy parameter at different $\frac{\text{flow depth}}{\text{vegetation height}}$ is derived, and a power-law profile is observed.