Laboratory Experiments on an Internal Solitary Wave over a Triangular Barrier

Mu, Haidi; Xu, Chong; Li, Qun

doi:10.1007/s11802-019-3943-1

Cited by 7 publications

(3 citation statements)

References 29 publications

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“…After reaching the maximum breaking depth, the vorticity continues to increase and starts to decrease slowly after the pycnocline reaches the initial equilibrium position. This development trend is similar to that of [16] on the interaction between internal waves and triangular obstacles.…”

Section: Distribution Of Vorticity Probability Density Distributionsupporting

confidence: 81%

“…As wave forcing continues to increase further, boluses are no longer able to form. Through evolution of interfacial internal solitary waves on a triangular barrier, Mu et al [16] found that wave instability creates dissipation of energy as it is transmitted from waves to turbulence. Rate of ISW energy dissipation, maximum turbulent dissipation and buoyancy diffusivity linearly increase with an increase in incident wave energy.…”

Section: Introductionmentioning

confidence: 99%

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Laboratory Studies of Internal Solitary Waves Propagating and Breaking over Submarine Canyons

Lin

Liu

Sheng³

et al. 2023

JMSE

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This paper carried out laboratory experiments to study evolution of internal solitary waves (ISWs) over submarine canyons with a combination of PIV (particle image velocimetry) and PLIF (planar laser-induced fluorescence) techniques. Taking canyon angle θ and collapse height ∆H as variables, Froude number Fr, head position, energy loss, vorticity field and turbulence intensity when ISWs propagate to the canyon were analyzed. According to the Froude number Fr values, the study cases can be divided into three types: Fr > 1.7 means complete internal hydraulic jump (IHJ); 1 < Fr < 1.7 denotes wavy IHJ and Fr < 1 represents no IHJ. The greater canyon angle, collapse depth and amplitude of the incident wave more easily generate IHJs, which can lead to more energy loss, greater vorticity and turbulence intensity in the canyon area. Among all canyon cases, vorticity and turbulence intensity of the no IHJ case showing an obvious bimodal distribution are smaller than IHJ cases. For wavy IHJ, the energy dissipation is not obvious, and the average turbulent intensity performs a “sharp unimodal distribution”. Complete IHJ cases last for a long time and cause violent mixing, the average turbulent intensity is the largest and its distribution presents a “gentle single peak” pattern. For the 180° conditions (no canyon cases), less energy is delivered to the reflected wave and more energy is dissipated near the terrain, so the energy loss is the largest in comparison to other conditions. These findings will deepen our understanding of the evolution mechanisms of ISWs propagating over submarine canyons.

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Section: Distribution Of Vorticity Probability Density Distributionsupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Laboratory Studies of Internal Solitary Waves Propagating and Breaking over Submarine Canyons

Lin

Liu

Sheng³

et al. 2023

JMSE

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“…laboratory observations of internal interfacial waves following the bow of a model ship -dead water phenomenon -towed on the surface of two-or three layer had been reported [81,128], and lee waves in downstream of artificial seamount at the bottom by pulling that seamount horizontally [129]. Freely propagating interfacial waves also were generated by gravitational collapse of dam-break flows from the side of the tank [130,131,132]. It is also possible that a recirculation system with a control unit ensures constant flow rates run from two separated sources with different densities for each layer in order to keep an uniform and unchangeable stratified flow, while the wave propagation is forced by a fixed obstacle at the bottom [133].…”

Section: Laboratory Wave Modelingmentioning

confidence: 99%

Experimental Analysis of Waves in Environmental Flows

Medjdoub

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This thesis presents three projects; two projects were conducted to study through laboratory experiments the applicability of linear wave theory on the prediction of interfacial internal waves in quasi-two-layer stratified water, and an additional project to study the complementarity of wind and solar energy resources for the electricity production in the north western of Africa.Interfacial internal wave excitation in the wake of towed ships is studied experimentally in a quasi-two-layer fluid. At a critical 'resonant' towing velocity, whose value depends on the structure of the vertical density profile, the amplitude of the internal wave train following the ship reaches a maximum, in unison with the development of a drag force acting on the vessel, known in the maritime literature as 'dead water'. The amplitudes and wavelengths of the emerging internal waves are evaluated for various ship speeds, ship lengths and stratification profiles. The results are compared to linear twoand three-layer theories of freely propagating waves and lee waves. We find that despite the fact that the observed internal waves can have considerable amplitudes, linear theories can still provide a surprisingly adequate description of subcritical-to-supercritical transition and the associated amplification of internal waves. We argue that the latter can be interpreted as a coalescence of frequencies of two fundamental stable wave motions, namely lee waves and propagating interfacial wave modes.The damping of water surface standing waves (seiche modes) and the associated excitation of baroclinic internal waves are studied experimentally in a quasi-two-layer laboratory setting with a topographic obstacle at the bottom representing a seabed sill.We find that topography-induced baroclinic wave drag contributes markedly to seiche damping in such systems. Two major pathways of barotropic-baroclinic energy conversions were observed: the stronger one -involving short-wavelength internal modes of large amplitudes -may occur when the node of the surface seiche is situated above the close vicinity of the sill. The weaker, less significant other pathway is the excitation of long waves or internal seiches along the pycnocline that may resonate with the low-frequency components of the decaying surface forcing. i We analyzed wind speed and solar irradiation data of high spatial and temporal resolution for an extended area of north-western Africa including the Mediterranean Sea.We ex-ploit the ERA5 data bank compiled and maintained by the European Centre for Medium Range Weather Forecast (ECMWF). One of the new products they provide is horizontal wind speed components at a height of 100 m (modern wind turbines have a hub height between 80 and 120 m). We demonstrate that the desert area is an optimal location for wind-and solar electricity production for two peculiar aspects. Firstly, the wind speeds at 100 m over the Sahara are al-most as large as wind speeds over the open sea. Wind speed differences between the standard 10 m altitude and 100 m level are...

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