Temporal and azimuthal dependence of sound propagation in shallow water with internal waves

Badiey, Mohsen; Mu, Yongke; Lynch, James F.; Apel, John R.; Wolf, Stephen N.

doi:10.1109/48.989898

Cited by 60 publications

(61 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From an acoustic point of view, the fixed source and receiver arrays focused the measurements of sound transmissions to two perpendicular paths: across the internal waves and along the waves. On the along waves acoustic path, strong acoustic horizontal ducting was observed in both the SWARM95 [8] and the SW06 experiments [14]. This geometry also allowed the experimenters to gather the first experimental evidence of the HLM pattern, a new three-dimensional acoustic effect (see Chapter 5) that had not been observed before (Badiey et.…”

Section: Internal Wavesmentioning

confidence: 79%

“…If internal waves were perfect reflectors at subcitical grazing angles, one would expect the intensity fluctuations in the along wave geometry to be much more than the observed 6-10 dB [8], according to Figs. 5-10 and 5-11.…”

Section: Secondary Ductingmentioning

confidence: 99%

“…Combination of ducting and antiducting events creates very significant scintillations of the acoustic intensity. These effects were first described for internal waves theoretically in [9] and numerically in [10,8]. The first experimental observations of these strong intensity fluctuations (6-10 dB) compared to the "no waves" case, with an along wave geometry for internal waves passing over a fixed source and receiver, were made during the SWARM95 experiment [8] and described in [50].…”

Section: Horizontal Acoustic Ductingmentioning

confidence: 99%

“…These effects were first described for internal waves theoretically in [9] and numerically in [10,8]. The first experimental observations of these strong intensity fluctuations (6-10 dB) compared to the "no waves" case, with an along wave geometry for internal waves passing over a fixed source and receiver, were made during the SWARM95 experiment [8] and described in [50]. Later, the SW06 experiment was specifically configured for measuring three-dimensional acoustic effects, and the intensity fluctuations in these directions were commonly observed in presence of internal wave trains [12].…”

Section: Horizontal Acoustic Ductingmentioning

confidence: 99%

“…Also as part of the SWARM95 experiment, Badiey [8] measured acoustic signals for an along waves path and showed that strong intensity fluctuations are caused by horizontal ducting of the acoustic signal between internal waves. This was the first experimental evidence of an out of vertical plane acoustic interaction with internal waves, which was predicted theoretically in [9] and numerically in [10,11].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Three-dimensional acoustic propagation through shallow water internal, surface gravity and bottom sediment waves

Shmelev¹

2011

View full text Add to dashboard Cite

This thesis describes the physics of fully three-dimensional low frequency acoustic interaction with internal waves, bottom sediment waves and surface swell waves that are often observed in shallow waters and on continental slopes. A simple idealized model of the ocean waveguide is used to analytically study the properties of acoustic normal modes and their perturbations due to waves of each type. The combined approach of a semi-quantitative study based on the geometrical acoustics approximation and on fully three-dimensional coupled mode numerical modeling is used to examine the azimuthal dependence of sound wave horizontal reflection from, transmission through and ducting between straight parallel waves of each type. The impact of the natural crossings of nonlinear internal waves on horizontally ducted sound energy is studied theoretically and modeled numerically using a three-dimensional parabolic equation acoustic propagation code. A realistic sea surface elevation is synthesized from the directional spectrum of long swells and used for three-dimensional numerical modeling of acoustic propagation. As a result, considerable normal mode amplitude scintillations were observed and shown to be strongly dependent on horizontal azimuth, range and mode number. Full field numerical modeling of low frequency sound propagation through large sand waves located on a sloped bottom was performed using the high resolution bathymetry of the mouth of San Francisco Bay. Very strong acoustic ducting is shown to steer acoustic energy beams along the sand wave's curved crests.

show abstract

Section: Internal Wavesmentioning

confidence: 79%

Section: Secondary Ductingmentioning

confidence: 99%