Turbulent flow structure across the spanwise edge of a canopy model

Abstract The turbulent flow field over a spanwise-heterogeneous vegetative canopy model was investigated to examine the impact of heterogeneity on energy and momentum transport processes. Constant temperature anemometry, paired with a novel Deep Learning-based calibration methodology, enabled high-resolution measurements of velocity components and turbulent kinetic energy (TKE) spectra, spanning several orders of magnitude and resolving dissipation scales. A controlled experimental framework facilitated the collection of multi-point, high-frequency turbulence statistics, capturing the intricate flow dynamics across canopy and open patch regions. In the homogeneous configuration, velocity profiles exhibited minimal variation across spanwise positions, with turbulence intensity peaking near the canopy height, where aerodynamic drag enhanced energy dissipation. Spectral analysis revealed distinct inertial and dissipation ranges, indicating the presence of robust turbulent structures that drive the energy cascade. In the heterogeneous layout, the boundary layer flow transitioned distinctly across the open patch, resembling rough plate behavior. Near canopy edges, elevated turbulence intensity, and TKE signaled strong interactions between vegetation and airflow, while TKE sharply diminished deeper into the open patch. Variations in turbulence length scales, particularly Taylor and horizontal integral scales, highlighted the role of heterogeneity in modulating atmospheric boundary layer dynamics. These findings provide insights into how spanwise heterogeneity influences turbulent energy redistribution and flow characteristics. The results contribute to a better understanding of canopy-atmosphere interactions and may support the refinement of models for predicting wind flow and transport phenomena in heterogeneous environments.