Thesis
Estructura del Flujo y Dinámica de los Vórtices en el Borde de Ataque de Semillas Autorrotantes (Swietenia macrophylla)
Autor
I G. SALCEDO ÁLVAREZ, ERICK
Institución
Resumen
An experimental investigation of near and far field aerodynamics of wind
dispersed seeds has been performed using digital stereoscopic particle image
velocimetry (DSPIV). As they fall, the spinning seeds generate a prominent
leading-edge vortex (LEV) which is responsible for augmenting lift forces.
In this work, the three-dimensional (3D) flow structures around free falling
autorotating Mahogany seeds in a vertical wind tunnel are revealed for the
first time. The results show that the LEV system is comprised of two vortical
elements: one primary vortex at the leading edge and one minor vortex at
the trailing edge. Thrust coefficients of the seeds were obtained using the
measured lift and drag coefficients, and terminal velocities were calculated
as a function of the Reynolds number and wing loading. Our experimental
findings indicate that the size of the LEV is larger than predicted in previous
two-dimensional (2D) studies. It is pointed out that studying pronounced 3D
flow using 2D approximations is prone to errors.