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On an Approximation to the Flow Through Axi-Symmetric Contracting Ducts

Published online by Cambridge University Press:  07 June 2016

R. Jordinson  and
J.G. Rodger
R. Jordinson
Affiliation:
Department of Mathematics, University of Edinburgh
J.G. Rodger
Affiliation:
Hydraulics Research Station, Wallingford, Berks
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Summary

A method is given for the calculation of incompressible, inviscid flow through an axi-symmetric contracting duct for which the two dimensional flow with the same meridianal boundaries is known. The method, which is based on Whitehead, Wu and Waters original proposal, assumes that the contraction consists of two separate portions, upstream and downstream respectively. The flow in each portion is calculated and the two portions matched to produce a contraction of given area ratio with preassigned values of the two dimensional ‘overshoot’ and ‘undershoot’ parameters. It is worth emphasizing that in practice it is only necessary to do the calculations once to predict wall velocities for a family of contraction shapes with different area ratios provided they share a common upstream or downstream portion. The results given here show reasonable agreement with the pressure coefficients obtained in experiment for the upstream end of a small scale contraction of area ratio 16:1. There is however a discrepancy between theory and experiment at the downstream end and a qualitative explanation is advanced for this.

Type
Research Article
Information
Aeronautical Quarterly , Volume 32 , Issue 1 , February 1981 , pp. 72 - 81
Copyright
Copyright © Royal Aeronautical Society. 1981

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References

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