Laboratory experiments on internal wave interactions with a pycnocline

2012 ◽  
Vol 53 (6) ◽  
pp. 1663-1679 ◽  
Author(s):  
Scott Wunsch ◽  
Alan Brandt
Keyword(s):  
Internal Wave ◽  
Laboratory Experiments ◽  
Wave Interactions

scholarly journals A Simple Parameterization of Turbulent Tidal Mixing near Supercritical Topography

2010 ◽  
Vol 40 (9) ◽  
pp. 2059-2074 ◽  
Author(s):  
Jody M. Klymak ◽  
Sonya Legg ◽  
Robert Pinkel
Keyword(s):  
Internal Wave ◽  
Water Column ◽  
Numerical Models ◽  
Tidal Flow ◽  
Internal Tides ◽  
Tidal Mixing ◽  
Knife Edge ◽  
Wave Interactions ◽  
Tidal Dissipation ◽  
Midocean Ridges

Abstract A simple parameterization for tidal dissipation near supercritical topography, designed to be applied at deep midocean ridges, is presented. In this parameterization, radiation of internal tides is quantified using a linear knife-edge model. Vertical internal wave modes that have nonrotating phase speeds slower than the tidal advection speed are assumed to dissipate locally, primarily because of hydraulic effects near the ridge crest. Evidence for high modes being dissipated is given in idealized numerical models of tidal flow over a Gaussian ridge. These idealized models also give guidance for where in the water column the predicted dissipation should be placed. The dissipation recipe holds if the Coriolis frequency f is varied, as long as hN/W ≫ f, where N is the stratification, h is the topographic height, and W is a width scale. This parameterization is not applicable to shallower topography, which has significantly more dissipation because near-critical processes dominate the observed turbulence. The parameterization compares well against simulations of tidal dissipation at the Kauai ridge but predicts less dissipation than estimated from observations of the full Hawaiian ridge, perhaps because of unparameterized wave–wave interactions.

Estimating pressure and internal-wave flux from laboratory experiments in focusing internal waves

2020 ◽  
Vol 61 (11) ◽  
Author(s):  
Pierre-Yves Passaggia ◽  
Vamsi K. Chalamalla ◽  
Matthew W. Hurley ◽  
Alberto Scotti ◽  
Edward Santilli
Keyword(s):  
Internal Wave ◽  
Internal Waves ◽  
Laboratory Experiments ◽  
Wave Flux

The Effects of Cracks and Fluids on Post-Seismic Healing

2020 ◽  
Author(s):  
Alison Malcolm ◽  
Somayeh Khajehpour Tadavani ◽  
Kristin Poduska
Keyword(s):  
Nonlinear Response ◽  
Laboratory Experiments ◽  
Recovery Process ◽  
Seismic Events ◽  
Wave Interactions ◽  
Material Control ◽  
Turn On ◽  
Nonlinear Mechanism ◽  
Underlying Mechanisms ◽  
Changing Noise

<p>It is now well established that large seismic events change the surrounding velocities, and that these velocities slowly recover over time.  Precisely which mechanisms control the recovery process are less well understood.  We present the results of laboratory experiments to better characterise what properties of the underlying material control the recovery process.  We do this by mixing two waves, one which perturbs the velocity of the sample (as an earthquake does in field data) and one which senses the change in velocity (as in changing noise correlations).  This is an inherently nonlinear experiment as we mix two waves and measure the effects of this wave mixing.  Within our experiments, we vary the properties of the samples to understand which are most important in controlling the nonlinear response.  We focus on two mechanisms.  The first is fractures and how changes in fracture properties change the nonlinear response.  The second is fluids, in particular the effect of low saturations on the nonlinear response.  By changing the fluids and fractures we can turn on and off the nonlinear mechanism, helping us to move toward a better understanding of the underlying mechanisms of these wave-wave interactions.</p>

scholarly journals Internal wave beam propagation in non-uniform stratifications

2009 ◽  
Vol 639 ◽  
pp. 133-152 ◽  
Author(s):  
MANIKANDAN MATHUR ◽  
THOMAS PEACOCK
Keyword(s):  
Internal Wave ◽  
Laboratory Experiments ◽  
Close Agreement ◽  
Wave Beam ◽  
Reflection Coefficients ◽  
Uniform Density ◽  
Finite Width ◽  
Transmission And Reflection Coefficients ◽  
Physical Quantities ◽  
Transmission And Reflection

In addition to being observable in laboratory experiments, internal wave beams are reported in geophysical settings, which are characterized by non-uniform density stratifications. Here, we perform a combined theoretical and experimental study of the propagation of internal wave beams in non-uniform density stratifications. Transmission and reflection coefficients, which can differ greatly for different physical quantities, are determined for sharp density-gradient interfaces and finite-width transition regions, accounting for viscous dissipation. Thereafter, we consider even more complex stratifications to model geophysical scenarios. We show that wave beam ducting can occur under conditions that do not necessitate evanescent layers, obtaining close agreement between theory and quantitative laboratory experiments. The results are also used to explain recent field observations of a vanishing wave beam at the Keana Ridge, Hawaii.

Numerical study of internal wave–wave interactions in a stratified fluid

2000 ◽  
Vol 415 ◽  
pp. 65-87 ◽  
Author(s):  
A. JAVAM ◽  
J. IMBERGER ◽  
S. W. ARMFIELD
Keyword(s):  
Internal Wave ◽  
Internal Waves ◽  
Numerical Study ◽  
Experimental Studies ◽  
Interaction Mechanism ◽  
Stratified Fluid ◽  
Interaction Region ◽  
Staggered Grid ◽  
Open Boundary ◽  
Wave Interactions

A finite volume method is used to study the generation, propagation and interaction of internal waves in a linearly stratified fluid. The internal waves were generated using single and multiple momentum sources. The full unsteady equations of motion were solved using a SIMPLE scheme on a non-staggered grid. An open boundary, based on the Sommerfield radiation condition, allowed waves to propagate through the computational boundaries with minimum reflection and distortion. For the case of a single momentum source, the effects of viscosity and nonlinearity on the generation and propagation of internal waves were investigated.Internal wave–wave interactions between two wave rays were studied using two momentum sources. The rays generated travelled out from the sources and intersected in interaction regions where nonlinear interactions caused the waves to break. When two rays had identical properties but opposite horizontal phase velocities (symmetric interaction), the interactions were not described by a triad interaction mechanism. Instead, energy was transferred to smaller wavelengths and, a few periods later, to standing evanescent modes in multiples of the primary frequency (greater than the ambient buoyancy frequencies) in the interaction region. The accumulation of the energy caused by these trapped modes within the interaction region resulted in the overturning of the density field. When the two rays had different properties (apart from the multiples of the forcing frequencies) the divisions of the forcing frequencies as well as the combination of the different frequencies were observed within the interaction region.The model was validated by comparing the results with those from experimental studies. Further, the energy balance was conserved and the dissipation of energy was shown to be related to the degree of nonlinear interaction.

Signatures of surface wave/internal wave interactions: Experiment and theory

1988 ◽  
Vol 12 (2) ◽  
pp. 89-106 ◽  
Author(s):  
J.R. Apel ◽  
R.F. Gasparovic ◽  
D.R. Thompson ◽  
B.L. Gotwols
Keyword(s):  
Surface Wave ◽  
Internal Wave ◽  
Wave Interactions

scholarly journals Description of nonlinear internal wave interactions using Langevin methods

1980 ◽  
Vol 85 (C2) ◽  
pp. 1085 ◽  
Author(s):  
Neil Pomphrey ◽  
James D. Meiss ◽  
Kenneth M. Watson
Keyword(s):  
Internal Wave ◽  
Wave Interactions ◽  
Nonlinear Internal Wave

Nonlinear Internal Wave Interactions with Low Frequency Shallow Water Sound—What is left to Do?

2010 ◽  
Author(s):  
James F. Lynch ◽  
Timothy F. Duda ◽  
Ying-Tsong Lin ◽  
Arthur E. Newhall ◽  
Jeffrey Simmen ◽  
...  
Keyword(s):  
Internal Wave ◽  
Shallow Water ◽  
Low Frequency ◽  
Wave Interactions ◽  
Nonlinear Internal Wave
Sign in / Sign up

Export Citation Format

Share Document