## Abstract

In the paper results of experiment ASIAEX 2001 are considered. Episodes are analysed when soliton-like nonlinear internal wave (NIW) moves approximately along acoustic track: from the source to receiver, located at the distance ~ 30 km from each other. The depth of the ocean changes from ~ 350 m near the source up to ~ 120 m near the receiver (Vertical Line Array). The source, placed near the bottom, transmitted pulses (M-sequences) with the frequency 224 Hz. It is shown that there are "predominating" frequencies in the spectrum of intensity fluctuations measured during ~ 6 hours of NIW motion from the source to receiver. Numerical modelling on the base of authors theory (Grigorev et al, JASA, v.140(5), 3980-3994, 2016) shows that peak frequencies correspond to the most strongly interacting pairs of modes: in given case pairs 2-3, 3-4. Due to narrowing channel velocity V of soliton should decrease; note that the corresponding change of the predominating frequency as a function of range (or time) was observed while soliton was moving. It is shown that if we take speed V as the fitting parameter then it is possible to estimate V of real soliton and its variation using comparison of experimental data and results of modelling. The corresponding procedure for episode where the comparison with direct measurement of velocity was done, gives values of V changing from 1.8 to 0.8 m/s, what is in a good agreement with experimental data.

Original language | English |
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Title of host publication | "Advances in Acoustics, Noise and Vibration - 2021" Proceedings of the 27th International Congress on Sound and Vibration, ICSV 2021 |

Editors | Eleonora Carletti, Malcolm Crocker, Marek Pawelczyk, Jiri Tuma |

Publisher | Silesian University Press |

ISBN (Electronic) | 9788378807995 |

State | Published - 2021 |

Event | 27th International Congress on Sound and Vibration, ICSV 2021 - Virtual, Online Duration: 11 Jul 2021 → 16 Jul 2021 |

### Publication series

Name | "Advances in Acoustics, Noise and Vibration - 2021" Proceedings of the 27th International Congress on Sound and Vibration, ICSV 2021 |
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### Conference

Conference | 27th International Congress on Sound and Vibration, ICSV 2021 |
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City | Virtual, Online |

Period | 11/07/21 → 16/07/21 |

### Bibliographical note

Funding Information:So we can see that measurement and analysis of the sound intensity fluctuations due to motion of nonlinear internal waves can give information about parameters of these waves. Work was supported by RFBR Grant 20-55-S52005

Publisher Copyright:

© "Advances in Acoustics, Noise and Vibration - 2021" Proceedings of the 27th International Congress on Sound and Vibration, ICSV 2021. All rights reserved.

## Keywords

- Mode coupling
- Nonlinear internal waves

## ASJC Scopus subject areas

- Acoustics and Ultrasonics