title: A study of autorotating plant seeds.
abstract: A leading edge vortex exists on the upper surface of an autorotating plant seed. The vortex enhances the vertical aerodynamic force acting on the seed and decreases the rate of descent. We analyzed the flight data of rotary seeds and revealed that the lift-drag ratio affects the descent factor more strongly than the vertical force coefficient. This has also been confirmed by falling tests of model rotors, which have various aspect ratios, airfoil shapes and total masses.
authors.affiliation: Osaka Prefecture University, Japan. Electronic address: sunada@aero.osakafu-u.ac.jp.
authors.forename: S
authors.initials: S
authors.lastname: Sunada
authors.affiliation: Osaka Prefecture University, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Ide
authors.affiliation: Osaka Prefecture University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hoshino
authors.affiliation: Kanazawa Institute of Technology, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Okamoto
mesh_terms: D000465:Algorithms; D001696:Biomechanical Phenomena; D008954:Models, Biological; D012212:Rheology; D012399:Rotation; D012639:Seeds / Q000033:anatomy & histology / Q000502:physiology*; D014197:Trees / Q000033:anatomy & histology / Q000502:physiology
keywords: Descent factor; Leading edge vortex; Lift–drag ratio; Vertical force coefficient