Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 74 for “"internal wave"”.
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Instabilities of finite-width internal wave beams
Internal gravity waves are fundamental to the dynamics of density stratified fluids and the instability mechanisms by which these waves dissipate their energy are a potentially significant factor that underlies the distribution of energy and momentum in the natural environment. Recently, it has …
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The development of nonlinear surface and internal wave groups
The development of nonlinear surface and internal wave groups is investigated. Surface wave evolution was observed in an unusually long wave channel as a function of steepness and group length. Dissipation and frequency downshifting were important characteristics of the long-time evolution. The …
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Experimental investigation of 2D and 3D internal wave fields
The generation of 2D and 3D internal wave fields is extensively studied via planarand stereo- Particle Image Velocimetry (PIV) flow field measurement techniques. A benchmark was provided by an experiment involving tidal flow over a 2D Gaussian ridge; this study providing a counterpart with which …
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The development of nonlinear surface and internal wave groups
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Meteorology and Physical Oceanography, 1982.
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Design of an internal wave generator for experimental applications
This thesis presents the design of an internal wave generator for experimental applications. It is based on the previous design by Gostiaux, Didelle, Mercier and Dauxois, however it is constructed on a smaller scale to be of use in one of the smaller tanks in the Nonlinear Dynamics Lab at MIT. The …
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Is the Indian Ocean MOC driven by internal wave breaking?
… I), and the interaction between a broad band internal wave field and a mean flow using idealized numerical simulations (Part II). The main objective of this work is to quantify how much energy is needed to drive the Indian Ocean MOC and to compare this with the energy available in the internal …
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Internal wave generation and its impact at the island Shelf
… circulation and the generation of nonlinear internal waves (NIWs) in the Madeira Archipelago, a region characterized by steep bathymetry, a narrow insular shelf, and strong atmosphere–ocean interactions. Although Madeira has been widely studied in terms of wake dynamics, mesoscale …
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Creation of nonlinear density gradients for use in internal wave research
… of water. Such gradients are useful for studying internal waves, an ocean phenomenon that plays an important role in climate and ocean circulation. The method was developed by expanding on the two-tank system currently used to create linear density gradients. A mathematical model of the two-tank …
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Visualizing internal wave generation by finite cylinder oscillations using stereo particle image velocimetry
This thesis investigates internal wave generation in a stratified fluid by means of an oscillating cylinder. We observe the consequences of boundary effects by the production of an out-of-plane velocity field as the cylinder span is decreased. Four cylinders are used. Stereoscopic PIV is utilized …
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Analysis of internal wave induced mode coupling effects on the 1995 SWARM experiment acoustic transmissions
… propagation direction for shelf generated internal wave solitons. Two models for the propagation of normal modes through a 2-D waveguide with solitary internal wave (soliton) scattering included are developed to help in understanding the very complicated mode arrivals seen at the WVLA. The …
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The rise and dilution of buoyant jets and their behaviour in an internal wave field
… one framework, and the effects of high-frequency internal waves on the motion of the buoyant jet. Past buoyant jet models were constructed for specific cases and their application is necessarily restricted. In this thesis, a new model is developed in a Lagrangian framework that can be applied to …
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Analysis of internal wave induced mode coupling effects on the 1995 SWARM experiment acoustic transmissions
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1997.
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Acoustic travel time perturbations due to an internal tide and internal wave field in the Barents Sea
… of adiabatic normal modes due to an internal tide and internal mode field in the Barents Sea are examined. A formalism for the travel time perturbation due to a change in sound speed is presented. Internal tide and internal wave amplitude spectra are calculated from Brancker …
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Surface wave, internal wave, and source motion effects on matched field processing in a shallow water waveguide
… the possible mismatch effects of surface and internal waves on matched field processing in a shallow water waveguide. We utilize a modified ray theory, based on the work of Tindle, to calculate the acoustic pressure field. This allows us to simply incorporate range dependent environmental …
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STRATIFIED WAKE SIGNATURES GENERATED BY PROPAGATING SUBMERGED BODIES IN THE PRESENCE OF AN ACTIVE INTERNAL WAVE FIELD
… a stratified wake in the presence of background internal waves using numerical simulations. To achieve this, we conducted numerical simulations on Department of Defense high-performance computing systems using the Massachusetts Institute of Technology general circulation model, which we adapted …
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Interpretation of equatorial current meter data as internal waves
… Munk use linear dynamics to synthesize frequency-wavenumber energy spectra for internal waves (GM72, GM75, GM79). The GM internal wave models are horizontally isotropic, vertically symmetric, purely propagating, and universal in both time and space. This set of properties effectively eliminates …
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Effects of internal waves on low frequency, long range, acoustic propagation in the deep ocean
… of acoustic fields after propagation through internal-wave-induced sound-speed fluctuations are explored experimentally and theoretically. The thesis starts with the investigation of the North Pacific Acoustic Laboratory 98-99 data by exploring the space-time scales of ocean sound speed …
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Effects of internal waves on low frequency, long range, acoustic propagation in the deep ocean
… of acoustic fields after propagation through internal-wave-induced sound-speed fluctuations are explored experimentally and theoretically. The thesis starts with the investigation of the North Pacific Acoustic Laboratory 98-99 data by exploring the space-time scales of ocean sound speed …
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The effect of internal waves on long range acoustic propagation in the ocean
The acoustic-internal wave interaction in an acoustic waveguide is investigated using wave techniques. Refractive index fluctuations due to the vertical displacements of the internal waves create an inhomogeneous waveguide. The analysis uses weak scattering theory based upon the Rytov perturbation …
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Observations of turbulence, internal waves and background flows : an inquiry into the relationships between scales of motion
… of turbulent mixing in the ocean due to internal waves. Turbulent mixing is quantified through eddy diffusivity parameterizations of the mass (Kρ; Osborn, 1980) and heat fluxes (Kτ; Osborn and Cox, 1972) in turbulent production/dissipation balances. Turbulence in the ocean is generally …
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