3 edition of Mixing and internal wave generation in dynamically unstable stratified jets. found in the catalog.
Mixing and internal wave generation in dynamically unstable stratified jets.
Bruce R. Sutherland
Written in English
Thesis (Ph.D.), Dept. of Physics, University of Toronto.
|Contributions||Peltier, W. R. (supervisor)|
|The Physical Object|
|Number of Pages||191|
Turbulence and Mixing in Stably Stratified Waters Turbulence and Mixing in Stably Stratified Waters Sherman, F S; Imberger, J; Corcos, G M Not only is mixing of stably stratified fluids an important element of many problems of oceanography, limnology, meteorology, and environmental engineering, but it also stands out from the infinite variety of turbulent flow phenomena . Oliver Fringer is part of Stanford Profiles, official site for faculty, postdocs, students and staff information (Expertise, Bio, Research, Publications, and more). The site facilitates research and collaboration in academic endeavors. These internal gravity waves result in momentum transport to a critical layer near the velocity maximum, where wave breaking and momentum absorption locally accelerates the flow in a fashion analogous to the well-postulated models of the sharpening of zonal jets cf. 26 – Internal gravity wave driven anti-diffusive momentum transport.
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Mixing and Internal Wave Generation in Dynamically Unstable Stratified Jets Sutherland, Bruce Ronald; Abstract. Stratified jets constitute a frequently observed class of geophysical flows that include the tropospheric jet stream in the atmosphere, the equatorial undercurrent in the oceans, and the super-rotational winds in the atmosphere of Author: Bruce Ronald Sutherland.
extended to the study of unstable jet flows and applications of this work for internal wave generation by dynamic instability of the upper flank of the jet stream are discussed. Introduction Although the most significant source of internal waves in the atmosphere is through topographic gen-eration, other sources of internal waves are not insig.
Numerical simulations have shown that this feedback is a robust feature of dynamically unstable wave generation in density stratified jets.
jet which mimics the internal wave related flow. THE GENERATION OF INTERNAL WAVES IN STRATIFIED FLUIDS I. INTRODUCTION In the laboratory, the standard method of generating. internal waves in a stratified fluid is osoil1ation of a solid example, Keu1egan and Carpenter ()* generated interfaoial progressive waves in.
Jets and waves, whose origin is in gravity force, are often observed in fluids. When the fluid has a vertical density stratification, both can be generated due to the buoyancy force. The jet appears when an obstacle descends vertically in a stratified fluid.
The generation is supported by the molecular diffusion of the stratifying scalar such Author: Hideshi Hanazaki. The mechanisms of generation of internal waves in the stratified fluid are not exactly known and they are still a subject of observation and numerical modelling.
Apart from the tides flowing over topography, the other driving force generating internal waves results are fluctuations of atmospheric pressure and sudden impact of stormy winds. B.R. Sutherland and W.R.
Peltier, “Turbulence Transition and Internal Wave Generation in Density Stratified Jets,” Phys. Fluids 6(3), – (). zbMATH CrossRef ADS Google Scholar P. Plaschko, “Helical Instabilities of Slowly Divergent Jets,” J.
Fluid Mech. 92 (Pt 2), – (). zbMATH CrossRef ADS Google Scholar. Future experiments will investigate nonlinear internal tide generation, overturning and mixing in unstable wave beams and flow separation over topography. by Paula Echeverri Mondragón.
S.M. View. The internal gravity wave field generated by a sphere towed in a stratified fluid was studied in the Froude number range [less-than-or-equal] F [less-than-or-equal]where F is defined. Parameterisation of the mixing due to breaking internal waves must account for the generation, propagation and dissipation of wave energy.
High resolution simulations can be used to examine the mechanisms of wave breaking, extending understanding gained from observations. The nonlinear evolution of an unstable symmetric jet in incompressible, density stratified fluid is simulated numerically.
When N 2 is constant and near zero, like‐signed vortices pair by way of an instability of the mean flow to a subharmonic disturbance with wavelength twice that of the most unstable mode of linear theory.
For small but finite and constant values of N 2, however, the. In continuously stratified fluid, vertically propagating internal gravity waves of moderately large amplitude can become unstable and possibly break due to a variety of mechanisms including (with some overlap) modulational instability, parametric subharmonic instability (PSI), self-acceleration, overturning, and convective instability.
In PSI, energy from primary waves is transferred, for. Dynamic instability Mixing and internal wave generation in dynamically unstable stratified jets. book stratified, By mixing the interface, each wave modifies the upstream condition for the next wave in the sequence and for the next wave train to propagate through that particular patch of fluid.
The idea that a highly nonlinear internal wave may exhibit vertical structure on scales much smaller than its dominant. The process of internal wave decay in this region is poorly understood. Internal waves have been observed to be actively overturning (e.g., Hebert et al. ) and have been correlated with enhanced turbulence kinetic energy (TKE) dissipation rates, ɛ, below the mixed layer (Moum et al.
; Hebert et al. ; Lien et al. ).Overturning waves, which are statically unstable, are. Linear theory for modes in a nonuniformly stratified, semi-infinite shear flow demonstrates that Rayleigh waves (stable waves propagating in fluid with spatially varying shear) couple with evanescent internal waves.
If the bulk Richardson number (the squared ratio of the buoyancy frequency and shear) lies between 1/4 and 1, the waves have infinite e -folding depth for waves with.
The geography of internal wave mixing thus is controlled by the combination of the generation geography, wave propagation and refraction, and processes that move energy toward smaller, more dissipative scales of motion.
Download: Download full-size image; Figure Global patterns of internal wave generation and propagation. Dynamics of internal jets in the merging of two droplets of unequal sizes - Volume - Chenglong Tang, Jiaquan Zhao, Peng Zhang, Chung K.
Law, Zuohua Huang. When the basic flow is time‐dependent, its stability analysis becomes more complicated. Drazin () has shown that a propagating unidirectional internal gravity wave is unstable for large local values of and Shefter () have constructed a family of explicit, elementary, stably‐stratified, time‐dependent and non‐parallel flows that are unstable for all arbitrarily large.
The work is extended to the study of unstable jet flows and applications of this work for internal wave generation by dynamic instability of the upper flank of the Jet Stream are discussed.
View. Turbulent mixing may be triggered by surface wind stress, frictional drag against the bottom, or dynamical instability of internal waves in stratified water. Turbulence, in turn, drains energy from the internal wave field and controls local stratification by.
New techniques for the generation and quantitative visualization of breaking progressive internal waves are presented. Laboratory techniques applicable to general stratified flow experiments are also demonstrated. The planar laser-induced fluorescence (PLIF) technique is used to produce calibrated images of the wave breaking process, and the details of the PLIF measurements are.
Internal wave reflection and mixing at Fieberling Guyot Charles C. Eriksen School of Oceanography, University of Washington, Seattle Abstract. The structure of internal wave reflection off a sloping bottom on the steep flank of a tall North Pacific Ocean seamount is observed in year-long moored array.
We examine mixed-layer deepening and the generation of internal waves in stratified fluid resulting from turbulence that develops in response to an applied surface stress. In laboratory experiments the stress is applied over the breadth of a finite. Introduction  The nonlinear internal waves (IWs) are widely acknowledged as being a small‐scale process with global and climatic significance.
They play a fundamental role in water mixing and, as a result, in the setting the global oceanic density structure. It is well established and proved nowadays fact that one of the most powerful and regular sources of internal waves is the.
of the jet (Figure 1b), which is an effect of stronger stratification (cf. JMNT). This results in a secondary peak for the fluctuating temperature variance (through the gradi-ent production) near the center of the jet (cf. Figure 2a). Withinthe core of the jet,oneither sides.
Internal wave excitation is the characteristic buoyancy frequency below the mixing region. By examining the growth and nonlinear development of the most unstable normal mode of an unstable hyperbolic tangent shear ﬂow with non-uniform strati cation in a periodic channel, Sutherland () has shown that strong excitation occurs if Jmix This paper reports on experimental observation of internal waves that are focused due to a sloping topography.
A remarkable mixing of the density fiel. The dilution then continues to increase with distance, but more slowly. The results are interpreted in terms of stratified turbulence collapse, and a model is proposed for the initial and final collapse of the turbulence in the jet.
Implications for mixing zone models are discussed. Estuarine, Coastal and Shelf Science () 22, Predictions of the Generation and Propagation of Internal Waves and Mixing in a Partially Stratified Estuary A. Newa.b, K. Dyer,c and R. Lewis" 'Institute of Oceanographic Sciences, Crossway, Taunton, Somerset and "ICI PLC, Brixham Laboratory, Freshwater Quarry, Brixham, Devon, England Received 7 September and.
The code was originally designed to model the evolution of unstable stratified parallel flows W.R. PeltierTurbulence transition and internal wave generation in density stratified jets. Physics of Fluids A, 6 (), pp. T.M. DillonInternal waves and mixing in the upper equatorial Pacific ocean.
Journal of Geophysical Research. Internal Gravity Wave Generation and Hydrodynamic Instability B. SUTHERLAND, C. CAULFIELD, AND W. PEI-TIER Department of Physics, University of Toronto, Toronto, Ontario, Canada (Manuscript received 27 Julyin final form 9 February ) ABSTRACT.
Internal waves (especially basin‐scale seiches) are often the most energetic motions in stratified lakes [Antenucci et al., ], providing the driving force for horizontal and vertical mixing [Ostrovsky et al., ].
Internal seiching motions induce currents along the sediment surface, creating a well‐mixed region referred to as the. AbstractA theory is developed for the baroclinic destabilization of density.
Zhang and O. Fringer,"A Numerical Study of Nonlinear Internal Wave Generation in the Luzon Strait", Proceedings of the 6th International Symposium on Stratified Flows, pp M. Barad, O. Fringer, and P. Colella,"Multiscale simulations of internal gravity waves", Proceedings of the 6th International Symposium on.
short internal waves that are first affected. Figure 2 shows the vertical wave number dependence for unstable conditions wherein the phase speed of the waves matches the current speed near the surface, resulting in a complex wave number component with a negative imaginary part (Fig.
2, right). In the. Turbulence transition and internal wave generation in density stratified jets B. Sutherland and W. Peltier, Phys.
Fluids, 6 (3), pp (). The nonlinear evolution of an unstable symmetric jet in incompressible, density stratified fluid is simulated numerically. A stably stratified fluid is one in which the fluid density increases with depth.
A characteristic of a stably stratified fluid is the ability to support and propagate wave motions. Except for a relatively thin layer in contact with the Earth's surface, i.e., the planetary boundary layer, the atmosphere is almost always stably stratified, and it is reasonable to assume that it always contains.
1. Introduction  Mixing in estuaries is a major factor affecting circulation, sediment transport, and the fate of pollutants.
The large impact of human development on estuarine environments makes imperative an effort to understand these systems. Internal mixing in shallow water stratified tidal flows is central to the understanding of salt wedge dynamics, yet is very difficult to measure.
The generation of unsteady internal lee waves and associated mixing was examined using the second tidal cycle. By this means the effects of transients during the “spin up” period were reduced.
 At t = 9/8T (where T is the M 2 tidal period) it is evident (Figure 2) that the. In many respects internal gravity waves (IGWs) still pose major questions both to the atmospheric and ocean sciences, and to stellar physics. Important issues are IGW radiation from their various relevant sources, IGW reflection at boundaries, their propagation through and interaction with a larger-scale flow, wave-induced mean flow, wave-wave interactions in general, wave breaking and its.
From an engineering perspective, internal waves affect the performance of underwater technology, such as acoustic communication, submersible vehicles and marine cabling. A detailed understanding of all aspects of internal wave generation and evolution is therefore both profoundly and practically important.At higher amplitude, however, a region develops near the critical level in which nonlinearity dominates, the wave packet becomes unstable, and the wavelike motion breaks down into smaller scales.
The form of the observed internal wave breakdown is unexpected in that convectively unstable density gradients persist for many buoyancy periods.Internal Wave Driven Mixing and Transport in the Coastal Ocean. stratified turbulence as well developing a theoretical framework for parameterizing mixing in stably and the generation of an internal hydraulic jump and the lee wave release during the ebb (slack) phase of the wave.