The Aerodynamics of Rapid Area Change in Perching Manoeuvres
Date
2015-02-02
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Abstract
This thesis presents a multidisciplinary study on bird perching to inspire Micro Aerial Vehicle design. Birds use a rapid pitch-up manoeuvre during perching, which modifies frontal area. Vorticity fields and forces are measured and simulated on an airfoil performing simultaneous deceleration and pitching to high angles of attack. Forces scale with the shape change number, a ratio between velocity of frontal area change and velocity change during deceleration. A simple analytical model agrees remarkably well with observed forces, and shows that the majority of forces are caused by boundary-layer separation and added-mass effects. Next, the kinematics of a small perching bird (the black-capped chickadee; Poecile atricapillus) are measured and parameterized with a three-dimensional analogue to the two-dimensional shape change number. The shape change numbers used by these birds are within the range of laboratory and computational tests discussed herein. These small birds use shape change numbers in proportion to the kinetic and potential energy at the start of the deceleration phase, in accordance with analytical predictions.
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Keywords
Fluid and Plasma, Engineering--Mechanical
Citation
Polet, D. (2015). The Aerodynamics of Rapid Area Change in Perching Manoeuvres (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/28007