Censor's Acoustical Doppler Effect Analysis--Is It a Valid Method

摘要

In the article, 'Acoustical Doppler effect analysis-Is it a valid method.' J. Acoust. Soc. Am. 83, 1223-1230 (1988), Censor considers the problem of scattering in the presence of moving objects under conditions of space and time dependent moving media. He considers this situation in the context of a generalized linear wave equation. This equation predicts the generation of Doppler type spectral components at frequencies that are equal to(i) the sum of the frequencies of the primary waves,(ii) the difference of the frequencies of the primary waves, and(iii) harmonics of these sum-and-difference frequencies. However, since the nonlinear wave equation also predicts scattered spectral components at these same frequencies, and since those predicted by the nonlinear theory are usually much stronger than those predicted by Censor's theory, the generalized linear wave equation used by Censor is generally inadequate for accurately predicting the amplitudes of the spectral components of interest. However, a limited regime is identified in which the spectral components predicted by Censor's theory can dominate those predicted by nonlinear theory. Keywords: Nonlinear acoustics; Scattering; Nonlinear scattering; Reprints. (jhd)