Frequency Dependence of Acoustic Fluctuations in a Randomly Inhomogeneous Medium

Autor:	D. Mintzer, E. O. LaCasce, R. G. Stone
Rok vydání:	1962
Předmět:	Physics Series (mathematics) business.industry Coefficient of variation General Physics and Astronomy Frequency dependence Standard deviation Computational physics Wavelength Amplitude Optics Range (statistics) business Refractive index
Zdroj:	Journal of Applied Physics. 33:2710-2714
ISSN:	1089-7550 0021-8979
DOI:	10.1063/1.1702536
Popis:	When a series of uniform acoustic pulses is transmitted through a medium whose refractive index varies in a random manner, the received pulses vary randomly about an average amplitude. A theory developed by Mintzer [J. Acoust. Soc. Am. 25, 922 (1953)] predicts that the coefficient of variation V, defined as the fractional standard deviation of a series of pulses, is directly proportional to k (2π/acoustic wavelength), provided that the range from the source to receiver is greater than ka2, where a is the correlation distance of the refractive index variations. In a scaled model experiment the refractive index variations are caused by heating the medium (water) from below, thus causing turbulent convection. Observations show the linear dependence of V upon frequency for r>ka2 as predicted by the theory. At the higher frequencies, observations indicate possible oscillations in V as it tends toward a frequency independent value.
Databáze:	OpenAIRE
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