Spherical Waves, Sources, and Multipoles
Sound rays, sound beams, plane waves, and cylindrical waves are possible only near a sound source. According to Huygen’s principle, every point in a wave front acts as a secondary source and propagates energy in all directions. This spreading out of the sound energy leads to a divergence of the sound waves so that, eventually, at great distances from the source, all sound waves become spherical waves. From a great distance, every sound source appears as the center of outgoing spherical waves.
KeywordsVolume Flow Sound Pressure Sound Source Radiation Resistance Sound Field
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- Brekhovskikh, L.: Reflection of spherical waves on the plane separation of two media. J. Tech. Phys. (U.S.S.R.) 18 (1948) 455–482 (in Russian).Google Scholar
- Horton, C. W., Sobey, A. E., Jr.: Studies on the near fields of monopole and dipole acoustic sources. J.A.S.A. 30 (1958) 1088.Google Scholar
- Ingard, U.: On the theory and design of acoustic resonators. J.A.S.A. 25 (1953) 1037.Google Scholar
- Ingard, U., Lamb, G. L., JR.: Effect of a reflecting plane on the power output of sound sources. J.A.S.A. 29 (1957) 743.Google Scholar
- Ingard, U., Lyon, R. H.: Impedance of a resistance loaded Helmholtz resonator. J.A.S.A. 25 (1953) 854.Google Scholar
- Karnovskh, M. I.: Interaction acoustical impedances of spherical radiators and resonators. Comptes Rendus (Doklady) de l’Académie des Sciences de l’URSS 32 (1941) 40–43.Google Scholar
- Mclachlan, N. W.: Loudspeakers. Oxford: Clarendon Press. 1934.Google Scholar
- Mcleroy, E. G.: Complex image theory of low-frequency sound propagation in shallow water. J.A.S.A. 33 (1961) 1120.Google Scholar
- Morse, P. M., Ingard, U.: Theoretical acoustics. New York, N. Y.: McGraw-Hill. 1968;Google Scholar
- Morse, P. M., Ingard, U.: Linear acoustic theory, p. 1–127 (in Handbuch der Physik, Vol. XI ). Berlin Göttingen—Heidelberg: Springer. 1962.Google Scholar
- Paul, D. I.: Acoustical radiation from a point source in the presence of two media. J.A.S.A. 29 (1957) 1102.Google Scholar