Horizontally refracted acoustic signals on the hind side of a solitary internal wave in shallow water.

2010 ◽  
Vol 128 (4) ◽  
pp. 2333-2333
Author(s):  
Mohsen Badiey ◽  
Boris Katsnelson ◽  
Ying‐Tsong Lin ◽  
James Lynch
Keyword(s):  
Internal Wave ◽  
Shallow Water ◽  
Acoustic Signals ◽  
Solitary Internal Wave

scholarly journals Numerical Investigation of Solitary Internal Wave-Induced Global Instability in Shallow Water Benthic Boundary Layers

2006 ◽  
Vol 36 (5) ◽  
pp. 784-812 ◽  
Author(s):  
Peter J. Diamessis ◽  
Larry G. Redekopp
Keyword(s):  
Boundary Layer ◽  
Internal Wave ◽  
Shallow Water ◽  
Water Column ◽  
Separation Bubble ◽  
Vertical Direction ◽  
Finite Difference Schemes ◽  
Global Instability ◽  
Solitary Internal Wave ◽  
Wave Induced

Abstract The time-dependent boundary layer induced by a weakly nonlinear solitary internal wave in shallow water is examined through direct numerical simulation. Waves of depression and elevation are both considered. The mean density field corresponds to that typical of the coastal ocean and lakes where the lower fraction of the water column is subject to the stabilizing effect of a diffuse stratification. Sufficient resolution of the “inviscid” dynamics of the boundary layer is ensured through use of a Legendre spectral multidomain discretization scheme in the vertical direction. At higher Reynolds numbers, where the simulations become underresolved, because of restrictions in available computational resources, spectral accuracy and numerical stability at the scales of physical interest are preserved through use of a penalty scheme in the vertical and explicit spectral filtering. Thus, a highly accurate description of the qualitative dynamics of the wave-induced global instability is possible and finescale physical mechanisms critical to the appearance of this instability are not smeared out by the high artificial dissipation inherent in lower-order finite-difference schemes. Results indicate that, for a wave amplitude exceeding a critical value, the global instability occurs in regions near the bottom boundary where the wave induces an adverse pressure gradient. The structure of the associated separation bubble is modified through the establishment of coherent and synchronous dynamics, characterized by elevated levels of bottom shear stress and a periodic shedding of coherent vortex structures. Although details of the vortex shedding depend on the particular wave forcing involved, these vortical structures always ascend high into the water column. All findings suggest that this global instability is a potent mechanism for benthic turbulence, mixing, and possible sediment resuspension in shallow waters, presumably even more intense than the nominal turbulent boundary layer.

A multi-layer model for nonlinear internal wave propagation in shallow water

2012 ◽  
Vol 695 ◽  
pp. 341-365 ◽  
Author(s):  
Philip L.-F. Liu ◽  
Xiaoming Wang
Keyword(s):  
Wave Propagation ◽  
Internal Wave ◽  
Shallow Water ◽  
Internal Waves ◽  
Bottom Topography ◽  
Laboratory Data ◽  
Constant Density ◽  
Layer Model ◽  
Fluid System ◽  
Nonlinear Internal Wave

AbstractIn this paper, a multi-layer model is developed for the purpose of studying nonlinear internal wave propagation in shallow water. The methodology employed in constructing the multi-layer model is similar to that used in deriving Boussinesq-type equations for surface gravity waves. It can also be viewed as an extension of the two-layer model developed by Choi & Camassa. The multi-layer model approximates the continuous density stratification by an $N$-layer fluid system in which a constant density is assumed in each layer. This allows the model to investigate higher-mode internal waves. Furthermore, the model is capable of simulating large-amplitude internal waves up to the breaking point. However, the model is limited by the assumption that the total water depth is shallow in comparison with the wavelength of interest. Furthermore, the vertical vorticity must vanish, while the horizontal vorticity components are weak. Numerical examples for strongly nonlinear waves are compared with laboratory data and other numerical studies in a two-layer fluid system. Good agreement is observed. The generation and propagation of mode-1 and mode-2 internal waves and their interactions with bottom topography are also investigated.

Acoustic mode coupling induced by internal wave fields in shallow water

1995 ◽  
Vol 98 (5) ◽  
pp. 2869-2869
Author(s):  
Steven Finette ◽  
Dirk Tielbuerger ◽  
Stephen Wolf
Keyword(s):  
Internal Wave ◽  
Shallow Water ◽  
Mode Coupling ◽  
Acoustic Mode ◽  
Wave Fields
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