Numerical Modeling of Free Surface Flow over Partially Flexible Vegetation under Different Submergence Variation

In this study, partial vegetation were modeled as flexible elements in a rectangular channel, and numerical simulations were performed to examine the flow dynamics occurring through and above submerged vegetation. The study specifically focused on assessing how the submergence ratio (SR), characterized as ratio of water flow depth to stem undeflected height, influence the flow behavior. The effects of vegetation and submergence circumstances on channel flow characteristics were investigated. FLUENT, a computational fluid dynamics (CFD) program, was used for numerical modeling. Sensitivity analyses regarding the turbulence model and mesh resolution were conducted utilizing the standard k–ε turbulence closure model with Reynolds averaged Navier-Stokes (RANS) equations. The outcome shows that the velocity along the channel is higher away from the vegetation area in the non-vegetated region and the space zone between two vegetation stems. The findings demonstrated that the proportion of discharge that passes through different regions within test domain and the flow obstruction are significantly impacted by the submergence state. Immediately behind the foliage, as opposed to the vegetation front, is where the increased turbulent kinetic energy is understood. The model is well-validated and agrees well with experimental data that is currently accessible in the literature. This research provided important light on the intricate relationship that turbulent flow and vegetation have in river ecosystems.