On the Transient Response of Rotors and Autorotating Seeds in Gusty Flows
Low-inertia rotors are present in quadrotors, micro aerial vehicles, and small wind and tidal turbines, to name but a few examples. The common practice of modelling the unsteady behaviour of low-inertia rotors using quasi-steady assumptions typically means poor rotor performance in unsteady (turbulent) flow environments. This thesis explores the behaviour of low-inertia rotors (and associated flow physics) so as to improve the unsteady performance of generic low-inertia rotor systems. Furthermore, lessons from the robust autorotation of samaras (e.g. maple seeds) in unsteady wind environments are extracted with the potential of applying such lessons in the design of efficient rotor systems. The four studies in this thesis experimentally characterize the unsteady response of low-inertia rotors and autorotating samaras experiencing a sudden change in flow, i.e. an axial gust. Low-inertia rotors are found to produce higher power output during the gust than for quasi-steady operation. To better describe the unsteady response of low-inertia rotors, a new dimensionless group, defining the influence of the rotor moment of inertia relative to the flow inertia, is introduced. Additionally, the kinematics of samaras experiencing canonical gusts, and related aerodynamic mechanisms, are explored experimentally using natural samaras as well as a samara-abstracted rotor. It is shown that natural samaras, and the samara-abstracted rotor, exhibit robust rotation under a variety of gust conditions.
URI for this recordhttp://hdl.handle.net/1974/28681
Request an alternative formatIf you require this document in an alternate, accessible format, please contact the Queen's Adaptive Technology Centre
The following license files are associated with this item: