Studies of shallow‐water acoustic coherence using the modal phase structure function

1999 ◽  
Vol 106 (4) ◽  
pp. 2303-2303
Author(s):  
Brian Sperry ◽  
James Lynch
Keyword(s):  
Structure Function ◽  
Shallow Water ◽  
Phase Structure

Vertical amplitude phase structure of a low-frequency acoustic field in shallow water

2016 ◽  
Vol 62 (6) ◽  
pp. 717-728
Author(s):  
G. N. Kuznetsov ◽  
O. V. Lebedev ◽  
A. N. Stepanov
Keyword(s):  
Shallow Water ◽  
Acoustic Field ◽  
Phase Structure ◽  
Low Frequency

scholarly journals Shallow water wave turbulence

2019 ◽  
Vol 874 ◽  
pp. 1169-1196 ◽  
Author(s):  
Pierre Augier ◽  
Ashwin Vishnu Mohanan ◽  
Erik Lindborg
Keyword(s):  
Reynolds Number ◽  
Structure Function ◽  
Shallow Water ◽  
Water Wave ◽  
Structure Functions ◽  
Wave Turbulence ◽  
Order Structure ◽  
Third Order ◽  
Shallow Water Wave ◽  
The Mean

The dynamics of irrotational shallow water wave turbulence forced at large scales and dissipated at small scales is investigated. First, we derive the shallow water analogue of the ‘four-fifths law’ of Kolmogorov turbulence for a third-order structure function involving velocity and displacement increments. Using this relation and assuming that the flow is dominated by shocks, we develop a simple model predicting that the shock amplitude scales as $(\unicode[STIX]{x1D716}d)^{1/3}$, where $\unicode[STIX]{x1D716}$ is the mean dissipation rate and $d$ the mean distance between the shocks, and that the $p$th-order displacement and velocity structure functions scale as $(\unicode[STIX]{x1D716}d)^{p/3}r/d$, where $r$ is the separation. Then we carry out a series of forced simulations with resolutions up to $7680^{2}$, varying the Froude number, $F_{f}=(\unicode[STIX]{x1D716}L_{f})^{1/3}/c$, where $L_{f}$ is the forcing length scale and $c$ is the wave speed. In all simulations a stationary state is reached in which there is a constant spectral energy flux and equipartition between kinetic and potential energy in the constant flux range. The third-order structure function relation is satisfied with a high degree of accuracy. Mean energy is found to scale approximately as $E\sim \sqrt{\unicode[STIX]{x1D716}L_{f}c}$, and is also dependent on resolution, indicating that shallow water wave turbulence does not fit into the paradigm of a Richardson–Kolmogorov cascade. In all simulations shocks develop, displayed as long thin bands of negative divergence in flow visualisations. The mean distance between the shocks is found to scale as $d\sim F_{f}^{1/2}L_{f}$. Structure functions of second and higher order are found to scale in good agreement with the model. We conclude that in the weak limit, $F_{f}\rightarrow 0$, shocks will become denser and weaker and finally disappear for a finite Reynolds number. On the other hand, for a given $F_{f}$, no matter how small, shocks will prevail if the Reynolds number is sufficiently large.

Phase structure function and AOA fluctuations of plane and spherical waves propagating through oceanic turbulence

2015 ◽  
Vol 17 (8) ◽  
pp. 085610 ◽  
Author(s):  
Lu Lu ◽  
Zhiqiang Wang ◽  
Pengfei Zhang ◽  
Chunhong Qiao ◽  
Chengyu Fan ◽  
...  
Keyword(s):  
Structure Function ◽  
Phase Structure ◽  
Spherical Waves ◽  
Oceanic Turbulence

Phase Structure Function Measurements With Multiple Apertures

1989 ◽  
Author(s):  
Frank D. Eaton ◽  
William A. Peterson ◽  
John R. Hines ◽  
James J. Drexler ◽  
Arthur H. Waldie ◽  
...  
Keyword(s):  
Structure Function ◽  
Phase Structure
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