Effect of added vorticity on trailing vortices in the extended near wake

Simple item page
dc.contributor.authorWood, Andrew Robert
dc.date.accessioned2013-07-23T13:25:17Z
dc.date.available2013-07-23T13:25:17Z
dc.date.issued2013-07-23
dc.description.abstractWind Tunnel testing of a rectangular semi-span NACA0012 wing with an actuating trailing edge flap and two small oscillating tabs, affixed to the model’s wingtip and flaptip, was undertaken with a view to introduce instabilities in the resulting wake. The tabs were oscillated sinusoidally at frequencies of 0.5, 1.0, and 2.0 Hz, both independently and together. The impact on the resulting wake was then studied; by examining the upper surface pressure distribution over the wing, and through images captured of the wake cross-section at three positions downstream of the model. Images were captured by seeding the flow with neutrally buoyant helium bubbles illuminated under a plane of light. Oscillation of the tabs at all frequencies was shown to impart instabilities in the near wake. The motion of the resulting vortex core under the oscillation of the tabs was mapped and shown to behave in a consistent manner through all angles of attack tested. An oscillation frequency of 2.0Hz showed the largest evidence of instabilities and greatest wake dispersion of the frequencies tested. A study into the transient pressure changes at the leading edge during oscillation of the tabs revealed a pressure oscillation equal to twice the frequency of the input tab oscillation. It was shown that synchronous oscillation of the two tabs at a frequency of 2.0 Hz, introduced sufficient instabilities into the flow to reduce the core diameter and wake extents of the primary wingtip vortex.en_ZA
dc.identifier.urihttp://hdl.handle.net/10539/12889
dc.language.isoenen_ZA
dc.titleEffect of added vorticity on trailing vortices in the extended near wakeen_ZA
dc.typeThesisen_ZA
Files
Original bundle
Now showing 1 - 2 of 2
No Thumbnail Available
Name:
MSc_AWood_0602037M.pdf
Size:
11.56 MB
Format:
Adobe Portable Document Format
Download
No Thumbnail Available
Name:
Abstract_AWood_0602037M.pdf
Size:
15.13 KB
Format:
Adobe Portable Document Format
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
ETD Collection