Computational analysis of fluid dynamics in open channel with the vegetated spur dike

Many rivers around the globe are characterized by steep gradients, leading to intense water velocity during flood events, often resulting in spur dikes being submerged. This study concentrates on exploring vegetated spur dikes, aiming not only to prevent from failure but also to enhance ecosystems and landscapes. The approach involves modifying existing emerged dikes by making it submerged and adding vegetations at the top. The vegetation aspect was simulated using wooden cylinders, varying in density (sparse, intermediate, and dense), and set under different spur dike width conditions. In this research, a three-dimensional computational modeling approach was utilized, incorporating FLUENT as the primary simulation tool. The study adopted the standard \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\:k-\epsilon\:$$\end{document} model to accurately simulate the flow dynamics. The reliability and precision of the numerical model were rigorously validated to ensure its accuracy. Findings indicated that spur dike width and vegetation density mutually influenced the depth-averaged velocity and the turbulence properties including turbulent kinetic energy, turbulent energy dissipation rate, and wall shear stress. Moreover, a direct correlation was observed between vegetation density and maximum flow deflection, whereas spur dike width also exhibited a significant influence on the spur dike field protection. Densely vegetated spur dikes showed a notable reduction of 48%, 36%, and 67% in the tip velocity, turbulent kinetic energy, and wall shear stress, respectively, compared to the case of submerged impermeable spur dike. Consequently, to protect spur dikes against intense turbulent flow, even under submerged conditions, the adoption of vegetated spur dikes is recommended.