Root Canopy Morphology Controls on Hydrodynamics and Turbulence Around Floating Vegetation Islands

ABSTRACT Floating vegetation islands (FVI) act as dynamic eco‐hydraulic elements in both natural and engineered waterways, yet their interactions with flow, particularly those influenced by root canopy morphology, remain insufficiently understood. This study employs a computational fluid dynamic (CFD)–based approach to investigate how different FVI root structures affect channel hydrodynamics and turbulence characteristics. The model was first validated and then used for simulation purposes. Three configurations were examined: tall roots (Case A), short roots (Case B) and a combination of tall and short roots (Case C). High‐resolution CFD simulations were conducted in a rectangular open channel to analyse flow velocity patterns, turbulence dynamics and bed shear responses around these FVI. The results reveal that vegetation morphology strongly governs flow behaviour and energy distribution. Case A produced substantial flow blockage, pronounced velocity gradients and extensive wake zones associated with heightened erosion potential. Case B induced moderate flow reduction and exhibited faster flow recovery, resulting in lower shear stress but limited flow attenuation. Case C demonstrated a balanced response, achieving moderate velocity reduction and more uniform turbulence distribution throughout the flow depth. Turbulence intensity and bed shear stress patterns also varied considerably among configurations: Case A concentrated turbulent kinetic energy and exhibited sharp stress gradients, Case B maintained more consistent profiles, and Case C displayed a spatially distributed turbulence field and intermediate stress variability, promoting stable sediment transport and ecological equilibrium. These findings underscore the pivotal role of vegetation (root canopy) arrangement in regulating flow resistance, sediment dynamics and ecological functionality, suggesting that strategically designed FVI can optimize erosion control, enhance habitat complexity and improve hydraulic performance in riverine and channelized systems.