Wind flow modifications induced by different configurations of vegetative barriers: a wind tunnel study

Abstract Vegetative barriers are commonly used to reduce wind velocity and mitigate dust dispersion and aeolian erosion. While their effectiveness has been widely demonstrated, the influence of plant spatial arrangement—particularly in multi-row configurations with varying heights—remains underexplored. This study presents a wind tunnel investigation of airflow modification by artificial vegetation models arranged in three configurations: a single row of trees and two multi-row layouts combining trees and shrubs (MR1: trees upstream and shrubs downstream; and MR2: shrubs upstream and trees downstream). Based on 2D laser Doppler velocimetry measurements, both streamwise ( U ) and vertical ( V ) components together with Reynolds shear stress ( $$\overline{u'v'}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mrow> <mml:msup> <mml:mi>u</mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:msup> <mml:mi>v</mml:mi> <mml:mo>′</mml:mo> </mml:msup> </mml:mrow> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> ) were analyzed to study the wake dynamics. The results show that MR1 (trees upstream) induces a more intense velocity reduction near the barrier, with 28% of the downstream area exhibiting a reduction in the streamwise velocity greater than 60%, and the mean reduction of the streamwise velocity is 57%, indicating stronger near-surface sheltering. In contrast, MR2 (shrubs upstream) promotes a smoother and more extended velocity recovery profile, with a mean reduction of streamwise velocity of 46%, favoring long-range mitigation. Despite having similar porosity, the vertical distribution of solid elements in MR1 increases the effective frontal blockage, enhancing aerodynamic resistance and flow deceleration. Turbulence analysis revealed that MR1 concentrates Reynolds shear stress near the ground, while MR2 shifts turbulent activity upward due to its vertical distribution of vegetation. These findings emphasize the role of barrier structure in shaping airflow patterns and provide experimental data for validating numerical models. The results contribute to the design of more efficient windbreak strategies adapted to specific environmental goals, such as erosion control or dust dispersion mitigation. They shed new light on the influence of the upstream–downstream distribution of vegetation heights.