Influence of Riparian Vegetation on Turbulent Flow around Submerged Spur Dike Fields

Spur dikes extend from the riverbanks into the main channel to serve various purposes. These structures create stagnant water zones, which influence the river ecosystem, sediment dynamics, and pollutant transport. Additionally, riparian vegetation contributes to these river processes during flooding. This study investigates the flow interactions between spur dike fields and the main channel to examine the effects of floodplain vegetation on mixing and the momentum exchange processes. Large Eddy Simulations were conducted with and without vegetation in a simplified straight channel within the OpenFOAM computational fluid dynamics framework. The results were analyzed to assess coherent structures, distributions of flow patterns, turbulent kinetic energy, and Reynolds stresses. Findings indicate that the presence of vegetation in the floodplain significantly alters the evolution of flow structures and mixing dynamics during river flooding. It also amplifies bed shear stress and turbulence in the main channel, which may induce bed erosion. This research advances insights into the complex flow dynamics of this coupled system, enhancing our understanding of flood management and vegetation restoration strategies.