Seminar 27th November 2012 4 p.m. Building 13, Room 3021
Proelastic Trailing Edge Noise and the Silent Flight of Owls
Justin Jaworski
University of Cambridge
- Categories
- Complex Systems
- Submitter
- Luke Goater
Abstract
Many owl species rely on specialised plumage to mitigate the generation of aerodynamic noise to realise functionally-silent flight whilst hunting. One such plumage feature, the arrangement of flexible trailing edge feathers, is idealised as a semi-infinite poroelastic plate to model the effects of edge compliance and flow seepage. The interaction of the poroelastic edge with a turbulent eddy is examined analytically with respect to the efficiency of scattered aerodynamic noise. The scattering problem is solved exactly using the Wiener-Hopf technique to identify the scaling dependence of the noise on the flight velocity, where special attention is paid to the limiting cases of rigid-porous and elastic-impermeable plate conditions. Results from this analysis identify parameter spaces where the porous and/or elastic properties of a trailing edge may be tailored to diminish or even eliminate the edge scattering effect and contribute to the understanding of the owl hush-kit.
Speaker Biography
Justin is based at the University of Cambridge and is a member of the Waves research group in the Department of Applied Mathematics and Theoretical Physics (DAMTP). His current research interests include the aeroacoustics of quiet biological fliers, the aerodynamic performance of flapping membrane wings in low Reynolds number flow, the nonlinear aeroelastic behaviour of high-aspect-ratio wings, and microscale power generation.