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A method of obtaining sub-critical compressible velocities for two-dimensional aerofoils from an exact inviscid incompressible solution

Published online by Cambridge University Press:  04 July 2016

B. Probert*
Affiliation:
Military Aircraft Division, British Aircraft Corporation

Extract

Numerical nominally-exact solutions of the full equations describing the inviscid compressible flow about two-dimensional aerofoils have been given by Nieuwland and Sells. However, these methods are not readily extendible to include such effects as viscosity and finite aspect ratio. Thus there is a general need for rapid approximate solutions. approximate solutions.

One such method is described in Ref. 3. The inviscid first-order (or pseudo first-order) solution given in Ref. 3 forms the basis of a standard, widely used, approximate method. It combines the small perturbation theory of Ref. 4 with an extended semi-empirical compressibility law originally derived for symmetrical aerofoils at zero incidence by Wilby. A detailed evaluation of the method is given in Ref. 6

Type
Technical Notes
Copyright
Copyright © Royal Aeronautical Society 1974 

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References

1. Nieuwland, G. Y. Transonic potential flow around a family of quasi-elliptical aerofoil sections. NLR TR 172, 1967.Google Scholar
2. Sells, C. C. L. Plane subcritical flow past a lifting aerofoil. RAE Report TR 67 146, 1967.Google Scholar
3. Lock, R. C. et al. The prediction of aerofoil pressure distributions for sub-critical viscous flows. Agard CP No 35, Paper No 12.Google Scholar
4. Weber, J. The calculation of the pressure distribution on the surface of thick cambered wings and the design of wings with given pressure distribution. ARC R & M 3026, 1957.Google Scholar
5. Wilby, P. G. The calculation of subcritical pressure distributions on symmetric aerofoils at zero incidence. NPL Aero Report 1208, ARC28 888-FM3822-Perf 2588, 7th March 1967.Google Scholar
6. Blockley, R. H. An evaluation of certain approximate methods for calculating subcritical pressure distributions on an aerofoil in compressible inviscid flow. To be issued. Google Scholar
7. Smith, A. M. O. and Pierce, J. Exact solution of the Neumann problem. Douglas Aircraft Co Report ES 26 988, 1958.Google Scholar
8. Loeve, W. and Slooff, J. W. On the applicability of the NLR and standard methods for calculation of sub-critical pressure distributions on wings. NLR AT-69-05.Google Scholar