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The air-injection method of fixing boundary-layer transition and investigating scale effects

Published online by Cambridge University Press:  04 July 2016

P. R. Ashill ,
J. L. Fulker  and
D. J. Weeks
P. R. Ashill
Affiliation:
Aerodynamics Department, RAE, Bedford
J. L. Fulker
Affiliation:
Aerodynamics Department, RAE, Bedford
D. J. Weeks
Affiliation:
Aerodynamics Department, RAE, Bedford
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Summary

The paper describes the air-injection method of fixing transition in wind-tunnel tests on a two-dimensional aerofoil and a swept panel at high subsonic free-stream speeds. The method is shown to provide a repeatable level of disturbance which, for a given flow condition, may be generated without interrupting the test and which appears not to cause a significant excess drag. Examples are given illustrating the effectiveness of the technique in demonstrating scale-sensitive features of flows, and a correlation is presented which allows the minimum value of air-injection mass flow needed to fix transition to be estimated from a knowledge of the behaviour of natural laminar flow on the wing.

Type
Research Article
Information
The Aeronautical Journal , Volume 91 , Issue 905 , May 1987 , pp. 214 - 224
Copyright
Copyright © Royal Aeronautical Society 1987 

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