Hydrodynamics of Vegetated Flows

Vegetated flows occur wherever water moves through or over stands of aquatic or riparian plants, creating a complex interaction between fluid motion and plant structure. At the stem and leaf scale, vegetation imposes a drag force that dissipates energy, alters velocity profiles and generates turbulence. Across a canopy, these local effects coalesce into distinct layers of flow with sharp velocity and shear gradients at the interface between densely vegetated and open‐water zones. This layered structure governs sediment transport, solute mixing and nutrient exchange, with direct consequences for flood attenuation, habitat quality and pollutant dispersion in rivers, wetlands and coastal systems. Understanding these processes demands an integrated view spanning laboratory experiments, field observations and numerical modelling, and must account for plant morphology, flexibility, density and submergence.

Research from Nature Portfolio

Recent studies have harnessed advanced data‐driven and experimental approaches to improve prediction and mechanistic understanding. A granular computing–artificial neural network framework has been developed to estimate longitudinal dispersion coefficients in vegetated channels under a wide range of flow and geometric conditions, explicitly quantifying uncertainty and achieving robust agreement with tracer measurements. Parallel experimental work on turbulent jets interacting with emergent vegetation arrays has revealed that rigid cylinder models reduce streamwise mixing but enhance transverse diffusion through intensified turbulent intensity and deflection around individual stems. Together, these investigations shed light on the interplay between plant structure and coherent flow features, informing both ecological assessments and engineering applications.

Hydrodynamics of Vegetated Flows publication trend

The graph below shows the total number of articles in hydrodynamics of vegetated flows across all publications each year (not limited to Nature Index journals).

Technical terms

Drag coefficient: dimensionless parameter quantifying the resistance exerted by vegetation elements on the flow.

Longitudinal dispersion coefficient: metric of mixing and spreading of solutes or particles along the flow direction due to combined advection and turbulence.

Shear layer: zone of strong velocity gradient at the boundary between vegetated and free‐flowing regions.

Canopy flow: flow regime occurring within and above vegetation, shaped by plant geometry, density and flexibility.

Turbulent diffusion: transport process driven by random, chaotic fluctuations in velocity that enhances mixing.

References

1. Uncertainty quantification of granular computing-neural network model for prediction of pollutant longitudinal dispersion coefficient in aquatic streams. Scientific Reports (2022).
2. How vegetation in flows modifies the turbulent mixing and spreading of jets. Scientific Reports (2017).
3. Flow resistance of floodplain vegetation mixtures for modelling river flows. Journal of Hydrology (2021).
4. Comparison of Flexible and Rigid Vegetation Induced Shear Layers in Partly Vegetated Channels. Water Resources Research (2021).