TY - GEN
T1 - Time-frequency analysis of acoustic modal intensity fluctuations induced by internal solitary wave packets
AU - Li, Qinran
AU - Sun, Chao
AU - Xie, Lei
N1 - Publisher Copyright:
© 2020 IEEE.
PY - 2020/10/5
Y1 - 2020/10/5
N2 - Modal intensity fluctuations caused by a moving nonlinear internal wave packet in a shallow water waveguide are investigated in this paper. An expression of the modal intensity is derived based on the coupled mode theory in a simple waveguide model. Theoretical calculations indicate that the time-varying modal interferences induced by mode coupling effects and mode stripping (different attenuation rates between different modes) give rise to the modal intensity fluctuations. The temporal variation of the oscillatory amplitude of an individual modal interference component is found to be dependent on the relationship between the attenuation rate of the observed mode arriving at receivers and that of the incident modes entering the internal solitary wave packet. The modal intensity fluctuations, characterized by the modal interferences with different frequency components and time-varying oscillatory amplitudes, are expected to have visible patterns in the time-frequency plane. The reassigned spectrogram with high time-frequency concentration is proved to be a desirable representation of the features of modal intensity fluctuations.
AB - Modal intensity fluctuations caused by a moving nonlinear internal wave packet in a shallow water waveguide are investigated in this paper. An expression of the modal intensity is derived based on the coupled mode theory in a simple waveguide model. Theoretical calculations indicate that the time-varying modal interferences induced by mode coupling effects and mode stripping (different attenuation rates between different modes) give rise to the modal intensity fluctuations. The temporal variation of the oscillatory amplitude of an individual modal interference component is found to be dependent on the relationship between the attenuation rate of the observed mode arriving at receivers and that of the incident modes entering the internal solitary wave packet. The modal intensity fluctuations, characterized by the modal interferences with different frequency components and time-varying oscillatory amplitudes, are expected to have visible patterns in the time-frequency plane. The reassigned spectrogram with high time-frequency concentration is proved to be a desirable representation of the features of modal intensity fluctuations.
KW - mode coupling effects
KW - Nonlinear internal waves
KW - underwater acoustic propagation
UR - http://www.scopus.com/inward/record.url?scp=85104616446&partnerID=8YFLogxK
U2 - 10.1109/IEEECONF38699.2020.9389205
DO - 10.1109/IEEECONF38699.2020.9389205
M3 - 会议稿件
AN - SCOPUS:85104616446
T3 - 2020 Global Oceans 2020: Singapore - U.S. Gulf Coast
BT - 2020 Global Oceans 2020
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2020 Global Oceans: Singapore - U.S. Gulf Coast, OCEANS 2020
Y2 - 5 October 2020 through 30 October 2020
ER -