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Numerical solution of conservation equations arising in linear wave theory: application to aeroacoustics

Published online by Cambridge University Press:  12 April 2006

SÉBastien M. Candel
Affiliation:
Office National d'Etudes et de Recherches AÉrospatiales (ONERA), and UniversitÉ de Technologie de Compiègne, 92320 Chatillon, France

Abstract

The propagation of waves in slightly inhomogeneous dispersive media is conveniently described by a geometrical or kinematic theory. In such frameworks the solution of the propagation problem is constructed by (a) deriving a dispersion relation and determining its characteristic lines and (b) solving an equation expressing the conservation of a field invariant like the wave action. This paper is concerned with the implementation of the last step under general field and boundary conditions. The method presented is based on the derivation of a variational system of differential equations for the geodesic elements of the wave front. The elementary cross-section of the wave front is obtained by integration and the principle of conservation of the field invariant directly yields the field amplitude. In addition, suitable jump conditions are derived for treating specular reflexions at solid boundaries. The method is illustrated by specific problems of interest in aeroacoustics.

Type
Research Article
Copyright
© 1977 Cambridge University Press

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References

Balsa, T. F. 1976 Refraction and shielding of sound from a source in a jet. J. Fluid Mech. 76, 443.Google Scholar
Belleval, J. F. De, Randon, J., Perulli, M. & Taillefesse, J. C. 1975 Influence of refraction effects on the interpretation of hot jet acoustic radiation. Prog. Astronaut. Aeronaut. 37, 93.Google Scholar
Blokhintsev, D. I. 1946 Acoustics of a non homogeneous moving medium. N.A.S.A. Tech. Memo. no. 1399.Google Scholar
Born, M. & Wolf, E. 1975 Principles of Optics, 5th ed. Pergamon.
Bretherton, F. P. & Garrett, C. G. R. 1968 Wave trains in inhomogeneous moving media. Proc. Roy. Soc. A 302, 529.Google Scholar
Candel, S. M. 1975 Acoustic conservation principles and an application to plane and modal propagation in nozzles and diffusers. J. Sound Vib. 41, 207.Google Scholar
Candel, S. M. 1976a Application of geometrical techniques to aeroacoustic problems. A.I.A.A. Paper no. 76–546.Google Scholar
Candel, S. M. 1976b Etudes théoriques et expérimentales de la propagation acoustique en milieu inhomogène et en mouvement. Thèse de Doctorat d'Etat, Université de Paris VI.
Candel, S. M., Guedel, A. & Julienne, A. 1975 Refraction and scattering in an open wind tunnel flow. Proc. 6th Int. Cong. Instrumentation in Aerospace Simulation Facilities, Ottawa, p. 288.
Candel, S. M., Guedel, A. & Julienne, A. 1976 Radiation, refraction and scattering of acoustic waves in a free shear flow. A.I.A.A. Paper no. 76–544.Google Scholar
Chen, D. C. & Ludwig, D. 1973 Calculation of wave amplitudes by ray tracing. J. Acoust. Soc. Am. 54, 431.Google Scholar
Csanady, G. T. 1966 The effect of mean velocity variation on jet noise. J. Fluid Mech. 26, 183.Google Scholar
Felsen, L. & Marcuvitz, N. 1970 Radiation and Scattering of Waves. Prentice Hall.
Fock, V. A. 1965 Electromagnetic Diffraction and Propagation Probléms. Pergamon.
Friedlander, F. G. 1958 Sound Pulses. Cambridge University Press.
Gossard, E. E. & Hooke, W. H. 1975 Waves in the Atmosphere. Elsevier.
Guiraud, J. P. 1965 Acoustique géométrique, bruit balistique des avions supersoniques et focalisation. J. Méc. 4, 215.Google Scholar
Hayes, W. D. 1968 Energy invariant for geometric acoustics in moving medium. Phys. Fluids 11, 1654.Google Scholar
Hayes, W. P. 1970 Kinematic wave theory. Proc. Roy. Soc. A 320, 209.Google Scholar
Hayes, W. P., Haefli, R. C. & Kulsrud, H. E. 1970 Sonic boom propagation in a stratified atmosphere with computer program. N.A.S.A. Contractor Rep. no. 1299.Google Scholar
Keller, J. B. 1954 Geometrical acoustics. I. The theory of weak shock waves. J. Appl. Phys. 25, 938.Google Scholar
Kline, M. 1961 A note on the expansion coefficient of geometrical optics. Comm. Pure Appl. Math. 15, 473.Google Scholar
Lighthill, M. J. 1972 The fourth annual Fairey lecture: the propagation of sound through moving fluids. J. Sound Vib. 24, 471.Google Scholar
Mackinnon, R. F., Partridge, J. S. & Toole, H. S. 1972 On the calculation of ray acoustic intensity. J. Acoust. Soc. Am. 52, 1471.Google Scholar
Mani, R. 1973 Refraction of acoustic duct wave guide modes by exhaust jets. Quart. Appl. Math. 30, 501.Google Scholar
Marcuse, D. 1972 Light Transmission Optics. Van Nostrand.
Quemada, D. 1968 Ondes dans les Plasmas. Paris: Hermann.
Schubert, L. K. 1972 Numerical study of sound radiation by a jet flow. I. Ray acoustics. J. Acoust. Soc. Am. 51, 439.Google Scholar
Solomon, L. P. & Armijo, L. 1971 An intensity differential equation in ray acoustics. J. Acoust. Soc. Am. 50, 960.Google Scholar
Struble, R. A. 1962 Nonlinear Differential Equations. McGraw-Hill.
Telford, W. M., Geldart, L. P., Sheriff, R. E. & Keys, D. A. 1976 Applied Geophysics. Cambridge University Press.
Ugincius, P. 1969 Intensity equations in ray acoustics I and II. J. Acoust. Soc. Am. 45, 193.Google Scholar
Urick, J. 1967 Principles of Underwater Sound. McGraw-Hill.
Whitham, G. B. 1974 Linear and Nonlinear Waves. Wiley.