Date of Award

Summer 2011

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical & Aerospace Engineering

Program/Concentration

Aerospace Engineering

Call Number for Print

Special Collections; LD4331.E535 C56 2011

Abstract

With fuel economy being a significant factor in today's world of aviation, aircraft manufacturers have been looking into ways to decrease drag to save fuel. Drag reduction using riblets on wing and fuselage surfaces is . an area that has been studied extensively for the last two decades. In preparation for a larger project which will use several methods to simulate this phenomena, small scale research had to be done to find ways to generate similar conditions on scaled models in a low speed wind tunnel and examine boundary layer behavior.

In this project, boundary layer measurement techniques, such as rake measurements and Preston tube measurements on a flat plate mounted on the wind tunnel side wall are presented with calibration techniques using "Design of Experiments" applied to electronic pressure scanners which were used to collect data. In addition, two methods to artificially thicken the boundary layer on a flat plate are presented in this thesis. The first technique is to use surface roughness elements and the second is to use a blowing technique in the wind tunnel.

Measurements show that boundary layer parameters are in good agreement with theoretical flat plate results according to the rake and Preston tube measurements. The Preston tube technique proves to be an effective method to measure skin friction coefficient on a surface. Surface roughness elements indicate that the ability to thicken the boundary layer is feasible in a low speed wind tunnel. Artificial thickening by blowing can be applied in a wind tunnel, but the volume coefficient should be sufficiently high. Nevertheless, the techniques presented in this paper are shown to be feasible. Finally, a FLOPS analysis also demonstrated the potential performance advantages for actual aircraft assuming that skin friction reduction techniques were successful.

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DOI

10.25777/08ba-y316

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