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On the design of three-dimensional wind tunnel contractions

Published online by Cambridge University Press:  04 July 2016

J. H. Downie ,
R. Jordinson  and
F. H. Barnes
J. H. Downie
Affiliation:
Department of Mechanical & Production Engineering, Brighton Polytechnic
R. Jordinson
Affiliation:
Department of Mechanical & Production Engineering, Brighton Polytechnic
F. H. Barnes
Affiliation:
Department of Mechanical & Production Engineering, Brighton Polytechnic
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Extract

A method is given for the calculation of incompressible inviscid flow through non-axisymmetric contracting ducts with rectangular cross-sections. The method is based on a finite difference approximation to Laplace's equation and solved by the method of successive over relaxation. In an attempt to provide practical criteria for the design of such contractions, the flows through a series of contraction shapes were calculated, each shape being based on a pair of matched elliptic arcs. This permitted choice of such parameters as length, local (ie two-dimensional) contraction ratio, position and magnitude of the maximum slope. It was found that reducing the length of the contraction also reduced its effective length, although increasing the effects of overshoot and undershoot. This could be compensated for by designing a contraction with a steep maximum slope which with associated low curvatures at entrance and exit reduced the values of overshoot and undershoot. The axial positions of maximum slope on wall and roof should be the same.

The predictions of the numerical method were tested against experiment and, in general, satisfactory comparisons were obtained.

Type
Research Article
Information
The Aeronautical Journal , Volume 88 , Issue 877 , February 2001 , pp. 287 - 295
Copyright
Copyright © Royal Aeronautical Society 1984 

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