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Upstream Shear Layer Stabilisation via Self-Oscillating Trailing Edge Flaplets

Talboys, E. and Bruecker, C. ORCID: 0000-0001-5834-3020 (2018). Upstream Shear Layer Stabilisation via Self-Oscillating Trailing Edge Flaplets. Experiments in Fluids, doi: 10.1007/s00348-018-2598-9

Abstract

The flow around a symmetric aerofoil (NACA 0012) with an array of flexible flaplets attached to the trailing edge has been investigated at Reynolds numbers of 100,000 - 150,000 by using time resolved particle image velocimetry (TR-PIV) and high speed motion tracking of the flaplets' tips. Particular attention has been made on the upstream effect on the boundary layer evolution along the suction side of the wing. For the plain aerofoil, without flaplets, the boundary layer on the second half of the wing undergoes shear-layer roll-up in the fundamental mode, but with rapid growth of non-linear modes which initiate the merging of rollers. When the flaplets are attached, it is shown that the flow-induced oscillations of the flaplets are able to create a lock-on effect that stabilises the linear state of the shear layer whilst damping the growth of non-linear modes. In addition, it is concluded that the modified trailing edge reduces aeroacoustic noise production in the lower frequency band, as indicated by an initial acoustic investigation.

Publication Type: Article
Additional Information: This is a pre-print of an article published in Experiments in Fluids. The final authenticated version will be available online at: http://link.springer.com/journal/348
Subjects: T Technology > TJ Mechanical engineering and machinery
Departments: School of Mathematics, Computer Science & Engineering > Engineering > Mechanical Engineering & Aeronautics
URI: http://openaccess.city.ac.uk/id/eprint/19585
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