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Temporal coherence of acoustic rays and modes using the path integral approach
1Naval Research Laboratory, 4555 Overlook Avenue, Washington, DC 20375, USA. tsihyang@gmail.com
The Journal of the Acoustical Society of America
|June 21, 2012
Summary
This study investigates acoustic propagation in shallow waters, focusing on how internal waves affect sound coherence. Numerical calculations show that internal waves cause mode coupling, leading to temporal coherence loss in the acoustic field.
Area of Science:
- Underwater acoustics
- Wave propagation physics
Background:
- Acoustic propagation is modeled using rays and normal modes.
- The mutual coherence function (MCF) describes acoustic field coherence.
- Shallow water acoustics involves boundary interactions, requiring combined vertical modes and horizontal rays.
Purpose of the Study:
- To derive the temporal coherence function for individual modes and the overall acoustic field.
- To analyze the impact of linear internal waves on acoustic temporal coherence.
- To quantify mode coupling effects caused by internal waves.
Main Methods:
- Application of path integral formulation to horizontal rays in shallow water.
- Derivation of the mutual coherence function for normal modes.
- Numerical calculations to illustrate temporal coherence loss due to internal wave-induced mode coupling.
Main Results:
- The study successfully derives the temporal coherence function for individual modes and the acoustic field.
- Internal waves induce mode coupling, significantly impacting temporal coherence.
- Numerical results demonstrate the extent of coherence loss caused by these effects.
Conclusions:
- The path integral method is effective for analyzing acoustic coherence in complex environments.
- Internal waves are a critical factor in shallow water acoustic temporal coherence.
- Mode coupling is a key mechanism for coherence degradation in the presence of internal waves.
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