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Seed dispersal mechanisms and their associated structural adaptations are crucial for maintaining biodiversity and ecological balance. Plants have evolved strategies to disperse seeds, including producing winged seeds capable of autorotational flight. The aerodynamic properties of wind-dispersed seeds exhibit remarkable efficiency in passive flight, making them an important subject of study for ecological and engineering applications. This study investigates the flight mechanics of three Brazilian Savanna species— Banisteriopsis laevifolia , Peixotoa tomentosa , and Qualea grandiflora —by analyzing their autorotational descent through experimental testing in a controlled environment. Key aerodynamic parameters, including terminal velocity, angular velocity, coning angle, wing loading, and power coefficient (C P ), were measured, calculated, and compared with theoretical predictions from rotor systems aerodynamics. The results confirm that wing loading strongly predicts descent behavior, and these seeds operate near-optimal rotor efficiency, akin to engineered rotor systems. The CP obtained for the studied samarids were 0.458 for B. laevifolia , 0.567 for P. tomentosa , and 0.587 for Q. grandiflora . These values compare favorably to conventional wind turbines, which typically range from 0.45 to 0.48, and approach the theoretical Betz limit of 0.593, highlighting the aerodynamic efficiency of these seeds as natural rotors, such as wind turbine applications.

The current study investigates the natural laminar-to-turbulent transition in the boundary layers of straight (STR) and swept (SWE) wings. The experiments are conducted in a subsonic low-speed wind tunnel using two wings configurations employing infrared thermography and pressure measurements. More specifically, image processing is used to analyze the flow pattern and infer the effects of Tollmien–Schlichting (T-S) and crossflow (CF) instabilities at low to moderate Re numbers (Re < 10 6 ), which is one of the main contributions of this research. Additionally, using the pressure distribution data as a reference, point analyses are conducted to explore the physical mechanisms of transition. The results of this study provide insight into the boundary layer transition region in straight and swept wings, concerning the effects of low Re numbers and their viscous associated implications, such as laminar separation bubbles (LSB) and adverse pressure gradient, phenomena that are encountered in many aerospace applications such as small UAVs with fixed wings.