Vorticity structures behind wing tips

Anderle, Pavel (2005) Vorticity structures behind wing tips. MSc(R) thesis, University of Glasgow.

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Abstract

This thesis describes an experimental investigation of the velocity and vorticity distributions in the flow field behind wing-tip devices. During the experimental programme, four types of full size wing-tips from the sailplanes were investigated experimentally. Effort was focused on gaining a greater understanding of how the wing-tip geometry modifies the vortex structure behind the wing. The research involved examining the velocity and vorticity distribution in the flow field, using hot-wire anemometry. In order to caiTy out measurements with the hotwire anemometry system, a new traverse mechanism was designed, manufactured and set-up. This traverse mechanism was integrated with the other test instrumentation to create a complete measurement chain. The complete system allows fully automated hot wire measurements to be made over a defined area using programmable test parameters. The measurements were perfomied in the Handley- Page wind tunnel of the Aerospace Engineering Department at the University of Glasgow. Firstly, the flow field behind a G-304 sailplane's standard wing-tip was measured to determine the vorticity structure and wing tip vortex location. The next step of the project was to test two versions of the G-304 sailplane's winglet and one wing-tip extension to clarify the effect these have on the vorticity structure and downwash distribution. The flow fields behind the wing tip models were measured in three planes at different angles of attack. For all tests the free stream velocity was set at 33 m/s (118.8 Km/h) which corresponds to a Reynolds number of Re = 0.8 x 106 based on the mean chord of the main wing. Data analyses and graphical presentations were carried out using Tecplot software in the form of vector plots of velocity distribution and contour line plots of the vorticity component. The results illustrate the effectiveness of the system in capturing the differences in the flow structures behind the various wing tip devices. They also highlight the role of the different wing tip slopes in modifying the wing induced flow field. This allows conclusions to be drawn in terms of the contribution of winglet to the total circulation and to the induced drag.

Item Type: Thesis (MSc(R))
Qualification Level: Masters
Additional Information: Adviser: Ing L Smrcek
Keywords: Aerospace engineering
Date of Award: 2005
Depositing User: Enlighten Team
Unique ID: glathesis:2005-71481
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 10 May 2019 14:32
Last Modified: 10 May 2019 14:32
URI: http://theses.gla.ac.uk/id/eprint/71481

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