scholarly journals Tidal Conversion and Dissipation at Steep Topography in a Channel Poleward of the Critical Latitude

2019 ◽  
Vol 49 (5) ◽  
pp. 1269-1291 ◽  
Author(s):  
Kenneth G. Hughes ◽  
Jody M. Klymak
Keyword(s):  
Three Dimensional ◽  
Tidal Energy ◽  
Kelvin Waves ◽  
Internal Tides ◽  
The Arctic ◽  
Energy Budgets ◽  
Dimensional System ◽  
Deep Layers ◽  
The Stability ◽  
Critical Latitude

Abstract In high-latitude fjords and channels in the Canadian Arctic Archipelago, walls support radiating internal tides as Kelvin waves. Such waves allow for significant barotropic to baroclinic tidal energy conversion, which is otherwise small or negligible when poleward of the critical latitude. This fundamentally three-dimensional system of a subinertial channel is investigated with a suite of numerical simulations in rectangular channels of varying width featuring idealized, isolated ridges. Even in channels as wide as 5 times the internal Rossby radius, tidal conversion can remain as high as predicted by an equivalent two-dimensional, nonrotating system. Curves of tidal conversion as a function of channel width, however, do not vary monotonically. Instead, they display peaks and nulls owing to interference between the Kelvin waves along the wall and similar waves that propagate along the ridge flanks, the wavelengths of which can be estimated from linear theory to guide prediction. Because the wavelengths are comparable to width scales of Arctic channels and fjords, the interference will play a first-order role in tidal energy budgets and may consequently influence the stability of glaciers, the ventilation of deep layers, the locations of sediment deposition, and the fate of freshwater exiting the Arctic Ocean.

scholarly journals Impact of Channel Geometry and Rotation on the Trapping of Internal Tides

2007 ◽  
Vol 37 (11) ◽  
pp. 2740-2763 ◽  
Author(s):  
Sybren Drijfhout ◽  
Leo R. M. Maas
Keyword(s):  
Continental Slope ◽  
Three Dimensional ◽  
Tidal Energy ◽  
Ocean Model ◽  
Internal Tides ◽  
Open Boundary ◽  
Kelvin Wave ◽  
Channel Geometry ◽  
Channel Slope ◽  
The Cross

Abstract The generation and propagation of internal tides has been studied with an isopycnic three-dimensional ocean model. The response of a uniformly stratified sea in a channel, which is forced by a barotropic tide on its open boundary, is considered. The tide progresses into the channel and forces internal tides over a continental slope at the other end. The channel has a length of 1200 km and a width of 191.25 km. The bottom profile has been varied. In a series of four experiments it is shown how the cross-channel geometry affects the propagation and trapping of internal tides, and the penetration scale of wave energy, away from the continental slope, is discussed. In particular it is found that a cross-channel bottom slope constrains the penetration of the internal tidal energy. Most internal waves refract toward a cross-channel plane where they are trapped. The exception is formed by edge waves that carry part of the energy away from the continental slope. In the case of rotation near the continental slope, the Poincaré waves that arise in the absence of a cross-channel slope no longer bear the characteristics of the wave attractor predicted by 2D theory, but are almost completely arrested, while the right-bound Kelvin wave preserves the 2D attractor in the cross-channel plane, which is present in the nonrotating case. The reflected, barotropic right-bound Kelvin wave acts as a secondary internal wave generator along the cross-channel slope.

Latitudinal Variation and Nonlinear Behavior of Internal Tides in the East China Sea

2020 ◽  
Author(s):  
Weidong Wang ◽  
Robin Robertson
Keyword(s):  
East China Sea ◽  
Wave Spectrum ◽  
Nonlinear Behavior ◽  
Tidal Energy ◽  
Internal Tides ◽  
East China ◽  
The East China Sea ◽  
Spectra Analysis ◽  
China Sea ◽  
Critical Latitude

<p>We present four sets of concurrent ADCP data obtained from the East China Sea shelf, and it suggests that near-inertial waves induced by parametric subharmonic instability (PSI) associated with harmonic transfer beyond diurnal critical latitude (O<sub>1</sub>:27.6°, K<sub>1</sub>:30°). Two type different nonlinear behavior (harmonic transfer and subharmonic transfer) occur varying with the latitude on different location. The velocity data indicated a transfer of diurnal internal tidal energy poleward of the diurnal critical latitude. Kinetic energy and shear spectra analysis at these moorings reveals that the prominent peaks enhance and appear at not only at the even order of diurnal tide such as semidiurnal band, 4cpd, 6cpd and even 8cpd, but also some unfamiliar odd harmonics 3cpd and 5cpd. Furthermore, additional energy is converted to higher mode locally through continuum internal wave spectrum. Besides the harmonic transfer, on the critical latitude for D<sub>2</sub>/2 wave(28.9°), D<sub>1</sub> wave is extracted from a D<sub>2</sub> tidal driven model output current. PSI conversion of semidiurnal internal tidal energy was confirmed by spectra analysis and bi-spectra, because of the distinguish of M<sub>2</sub>/2 separated from the diurnal tidal (O<sub>1</sub>, K<sub>1</sub>).</p>

scholarly journals CHANGES IN THE HYDROLOGICAL CHARACTERISTICS OF THE ARCTIC OCEAN UNDER THE INFLUENCE OF INCREASING RIVER RUNOFF

2021 ◽  
Vol 4 (1) ◽  
pp. 210-216
Author(s):  
Marina A. Tarkhanova ◽  
Elena N. Golubeva
Keyword(s):  
Arctic Ocean ◽  
River Runoff ◽  
Three Dimensional ◽  
Heat Content ◽  
Water Layer ◽  
Atlantic Water ◽  
Reanalysis Data ◽  
The Arctic ◽  
The Stability ◽  
Stability Of Water

The paper considers issues related to the influence of increased Arctic river runoff on the formation of the thermohaline structure of waters outside the Arctic shelf and, in particular, on the variability of heat content of the deep Arctic Ocean. The study is carried out using the three-dimensional numerical model of the ocean and sea ice SibCIOM and atmospheric reanalysis data NCEP/NCAR. Numerical simulation results showed that increased flow of Arctic rivers contributes to the stability of water stratification outside the shelf areas, which reduces the depth of autumn-winter mixing and allows Atlantic waters spreading along the continental slope to retain their heat. This is evidenced by an increase in the heat content of the upper 200 m layer waters of the eastern Eurasian basin and the rise of the Atlantic water layer upper boundary in this region.

scholarly journals Dynamics and Energetics of Trapped Diurnal Internal Kelvin Waves around a Midlatitude Island

2017 ◽  
Vol 47 (10) ◽  
pp. 2479-2498 ◽  
Author(s):  
Eiji Masunaga ◽  
Oliver B. Fringer ◽  
Yujiro Kitade ◽  
Hidekatsu Yamazaki ◽  
Scott M. Gallager
Keyword(s):  
Three Dimensional ◽  
Internal Tide ◽  
Kelvin Waves ◽  
Internal Tides ◽  
Navier Stokes ◽  
Kelvin Wave ◽  
Sagami Bay ◽  
Study Region ◽  
Topographic Slope ◽  
Terrain Following

AbstractThe generation of trapped and radiating internal tides around Izu‐Oshima Island located off Sagami Bay, Japan, is investigated using the three-dimensional Stanford Unstructured Nonhydrostatic Terrain-following Adaptive Navier–Stokes Simulator (SUNTANS) that is validated with observations of isotherm displacements in shallow water. The model is forced by barotropic tides, which generate strong baroclinic internal tides in the study region. Model results showed that when diurnal K1 barotropic tides dominate, resonance of a trapped internal Kelvin wave leads to large-amplitude internal tides in shallow waters on the coast. This resonance produces diurnal motions that are much stronger than the semidiurnal motions. The weaker, freely propagating, semidiurnal internal tides are generated on the western side of the island, where the M2 internal tide beam angle matches the topographic slope. The internal wave energy flux due to the diurnal internal tides is much higher than that of the semidiurnal tides in the study region. Although the diurnal internal tide energy is trapped, this study shows that steepening of the Kelvin waves produces high-frequency internal tides that radiate from the island, thus acting as a mechanism to extract energy from the diurnal motions.

scholarly journals Model Simulation of M2 Internal Tide at the Mariana Double Ridges

2021 ◽  
Vol 9 (6) ◽  
pp. 592
Author(s):  
Qi’an Chen ◽  
Liu Yu ◽  
Qingxuan Yang ◽  
Philip Vetter ◽  
Hongzhou Xu ◽  
...  
Keyword(s):  
Model Simulation ◽  
Three Dimensional ◽  
Internal Tide ◽  
Tidal Energy ◽  
Energy Budgets ◽  
Flux Divergence ◽  
Diapycnal Mixing ◽  
Budget Analysis ◽  
O 10 ◽  
Double Ridge

In this study, M2 tidal energy and tide-induced mixing in the Mariana double ridges are investigated with a high-resolution three-dimensional non-hydrostatic numerical model and baroclinic energy budget analysis. The interference effect of the double ridges on the internal tide in the Mariana is examined by omitting either the eastern or the western ridge. Our results show that the baroclinic velocity on the sides of the interior facing slopes of the double ridges is larger than that on the other sides. In the double ridges, high values of dissipation reaching O (10−6 W kg−1) are accompanied by diapycnal diffusivity reaching O (10−1 m2 s−1), which is several orders of magnitude higher than the mixing of the open ocean. The bottom diapycnal mixing in the inner region between the two ridges is one order of magnitude larger than the mixing outside the ridges, indicating the important role of the interference of the double-ridge topography on the mixing in the Mariana Arc. Omitting either the eastern or the western ridge would have a significant impact on tide current, baroclinic energy flux and dissipation, and diapycnal mixing. The internal tide conversion, dissipation, and flux divergence are amplified by the double ridge topography, especially in the central part of the double ridges. Through energy budgets analysis, we conclude that the eastern ridge is the main source of the baroclinic tide in the Mariana double ridges.

Crystal structure, hydrogen bonds and thermal transformations of superprotonic conductor Cs6(SO4)3(H3PO4)4

2021 ◽  
Vol 77 (2) ◽  
Author(s):  
Irina Makarova ◽  
Elena Selezneva ◽  
Laura Canadillas-Delgado ◽  
Estelle Mossou ◽  
Aleksander Vasiliev ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Hydrogen Bonds ◽  
Neutron Diffraction ◽  
Three Dimensional ◽  
Dimensional System ◽  
Polarization Microscopy ◽  
Cubic Symmetry ◽  
Temperature Changes ◽  
Minimum Potential ◽  
The Stability

Crystals of Cs6(SO4)3(H3PO4)4 belong to the family of alkali metal acid salts that show a high protonic conductivity at relatively low temperatures. Such properties make superprotonic crystals an excellent choice for the study of the influence of the hydrogen subsystem on the physicochemical properties and promising materials for energy-efficient technologies. Single crystals of Cs6(SO4)3(H3PO4)4 were studied by neutron diffraction methods, optical polarization microscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Neutron diffraction studies made it possible to determine the positions of all the atoms with high accuracy, including the H atom on a hydrogen bond characterized by a single-minimum potential, to confirm the chemical composition of the Cs6(SO4)3(H3PO4)4 crystals and their cubic symmetry in low- and high-temperature phases, and to draw conclusions about the three-dimensional system of hydrogen bonds, which is fundamentally different in comparison with other superprotonic compounds. Based on the experimental data obtained, crystal transformations with temperature changes are reported, and the stability of the chemical composition is shown.

scholarly journals The evolution of developmental patterning under genetic duplication constraints

2007 ◽  
Vol 5 (19) ◽  
pp. 237-245 ◽  
Author(s):  
Miguel A Fuentes ◽  
David C Krakauer
Keyword(s):  
Gene Duplication ◽  
Phenotypic Variability ◽  
Three Dimensional ◽  
Evolutionary Process ◽  
Evolutionary Model ◽  
Dimensional System ◽  
Genetic Robustness ◽  
Complex Adaptive ◽  
Duplication Events ◽  
The Stability

Of considerable interest are the evolutionary and developmental origins of complex, adaptive structures and the mechanisms that stabilize these structures. We consider the relationship between the evolutionary process of gene duplication and deletion and the stability of morphogenetic patterns produced by interacting activators and inhibitors. We compare the relative stability of patterns with a single activator and inhibitor (two-dimensional system) against a ‘redundant’ system with two activators or two inhibitors (three-dimensional system). We find that duplication events can both expand and contract the space of patterns. We study developmental robustness in terms of stochastic escape times from this space, also known as a ‘canalization potential’. We embed the output of pattern formation into an explicit evolutionary model of gene duplication, gene loss and variation in the steepness of the canalization potential. We find that under all constant conditions, the system evolves towards a preference for steep potentials associated with low phenotypic variability and longer lifespans. This preference leads to an overall decrease in the density of redundant genotypes as developmental robustness neutralizes the advantages of genetic robustness.

PERIODIC ORBITS OF THE LORENZ SYSTEM THROUGH PERTURBATION THEORY

2001 ◽  
Vol 11 (10) ◽  
pp. 2559-2566 ◽  
Author(s):  
J. PALACIÁN ◽  
P. YANGUAS
Keyword(s):  
Periodic Orbits ◽  
Lorenz System ◽  
Linear Part ◽  
Three Dimensional ◽  
Invariant Sets ◽  
Dimensional System ◽  
The Matrix ◽  
Lie Transformations ◽  
The Lorenz System ◽  
The Stability

Different transformations are applied to the Lorenz system with the aim of reducing the initial three-dimensional system into others of dimension two. The symmetries of the linear part of the system are determined by calculating the matrices which commute with the matrix associated to the linear part. These symmetries are extended to the whole system up to an adequate order by using Lie transformations. After the reduction, we formulate the resulting systems using the invariants associated to each reduction. At this step, we calculate for each reduced system the equilibria and their stability. They are in correspondence with the periodic orbits and invariant sets of the initial system, the stability being the same.

scholarly journals Internal wave generation by oscillation of a sphere, with application to internal tides

2010 ◽  
Vol 666 ◽  
pp. 308-357 ◽  
Author(s):  
B. VOISIN ◽  
E. V. ERMANYUK ◽  
J.-B. FLÓR
Keyword(s):  
Wave Amplitude ◽  
Near Field ◽  
Oscillation Amplitude ◽  
Tidal Flow ◽  
Three Dimensional ◽  
Tidal Energy ◽  
Internal Gravity Waves ◽  
Internal Tides ◽  
Correlation Technique ◽  
The Waves

A joint theoretical and experimental study is performed on the generation of internal gravity waves by an oscillating sphere, as a paradigm of the generation of internal tides by barotropic tidal flow over three-dimensional supercritical topography. The theory is linear and three-dimensional, applies both near and far from the sphere, and takes into account viscosity and the unsteadiness arising from the interference with transients generated at the start-up. The waves propagate in conical beams, evolving with distance from a bimodal to unimodal wave profile. In the near field, the profile is asymmetric with its major peak towards the axis of the cones. The experiments involve horizontal oscillations and develop a cross-correlation technique for the measurement of the deformation of fluorescent dye planes to sub-pixel accuracy. At an oscillation amplitude of one fifth of the radius of the sphere, the waves are linear and the agreement between experiment and theory is excellent. As the amplitude increases to half the radius, nonlinear effects cause the wave amplitude to saturate at a value that is 20% lower than its linear estimate. Application of the theory to the conversion rate of barotropic tidal energy into internal tides confirms the expected scaling for flat topography, and shows its transformation for hemispherical topography. In the ocean, viscous and unsteady effects have an essentially local role, in keeping the wave amplitude finite at the edges of the beams, and otherwise dissipate energy on such large distances that they hardly induce any decay.

A Liquid Metal Flow Between Two Coaxial Cylinders System

2019 ◽  
Vol 11 (1) ◽  
pp. 79-86
Author(s):  
Abdelkrim Merah ◽  
Ridha Kelaiaia ◽  
Faiza Mokhtari
Keyword(s):  
Couette Flow ◽  
Metal Flow ◽  
Three Dimensional ◽  
Liquid Sodium ◽  
Taylor Vortex ◽  
Turbulent Regime ◽  
Coaxial Cylinders ◽  
Concentric Cylinders ◽  
Ideal Tool ◽  
The Stability

Abstract The Taylor-Couette flow between two rotating coaxial cylinders remains an ideal tool for understanding the mechanism of the transition from laminar to turbulent regime in rotating flow for the scientific community. We present for different Taylor numbers a set of three-dimensional numerical investigations of the stability and transition from Couette flow to Taylor vortex regime of a viscous incompressible fluid (liquid sodium) between two concentric cylinders with the inner one rotating and the outer one at rest. We seek the onset of the first instability and we compare the obtained results for different velocity rates. We calculate the corresponding Taylor number in order to show its effect on flow patterns and pressure field.

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