Since the Morfey-Howell Q/S was introduced as a single-point frequency-domain nonlinearity indicator for propagation of intense broadband noise [AIAA J. 19, 986-992 (1981)], there has been debate about its validity, utility, and interpretation. In this Letter, the generalized Burgers equation is recast in terms of specific acoustic impedance along with linear absorption and dispersion coefficients, normalized quadspectral density (Q/S), and newly proposed normalized cospectral density (C/S). The formulation leads to a rather straightforward interpretation in which Q/S and C/S, respectively, represent the additional absorption and dispersion at a locale, produced by the passage of a finite-amplitude wave.
|Journal||Journal of the Acoustical Society of America|
|Publication status||Published - 2020 Sept 1|
Bibliographical noteFunding Information:
W.-S.O. gratefully acknowledges the generous support from the Department of Physics and Astronomy, Brigham Young University. The authors thank Brent O. Reichman for helpful discussions.
© 2020 Acoustical Society of America.
All Science Journal Classification (ASJC) codes
- Arts and Humanities (miscellaneous)
- Acoustics and Ultrasonics