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Interference Effects at Sonic Speeds for a Biconvex Aerofoil in a Wind Tunnel with Slotted Liners

Published online by Cambridge University Press:  04 July 2016

W. J. Graham  and
A. G. J. MacDonald
W. J. Graham
Affiliation:
Aerodynamics Division, National Physical Laboratory
A. G. J. MacDonald
Affiliation:
Aerodynamics Division, National Physical Laboratory
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Extract

The purpose of this note is to present some recently acquired data showing the effects of variations in the open area of slotted liners on the pressures on a twodimensional aerofoil at sonic speed in the 36 inch X 14 inch transonic wind tunnel at the NPL. The basic slotted liners for this tunnel have eleven longitudinal slots, giving an open-area ratio (σ) of 0.091. Other slot openings are obtained by closing appropriate slots with “Sellotape.” Nine values of σ ranging from 0 to 0.091, were used in this investigation. A wall static-pressure orifice, sufficiently far upstream of the model to be unaffected by its presence (3-6 chords), was used as a reference pressure for tunnel speed. The relationship between the Mach number given by this reference pressure and the true tunnel Mach number (M0), at the model location, was obtained by careful calibration.

Type
Technical Notes
Information
The Aeronautical Journal , Volume 70 , Issue 663 , March 1966 , pp. 446 - 448
Copyright
Copyright © Royal Aeronautical Society 1966

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References

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