On leakage of energy from turbulence to internal waves in the oceanic mixed layer

Kantha, Lakshmi; Clayson, Carol Anne

doi:10.1007/s10236-006-0100-3

Cited by 7 publications

(3 citation statements)

References 31 publications

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“…implemented. Specifically, second moment closure (SMC) models of turbulent mixing (e.g., Kantha and Clayson, 2007) have enabled more accurate simulations of oceanic mixing processes, although there is still room for improvement. Recently, Kantha and Carniel (2009) refined turbulence models of stably stratified flows to allow mixing at all values of the gradient Richardson number.…”

Section: Discussionmentioning

confidence: 99%

Physical forcing and physical/biochemical variability of the Mediterranean Sea: a review of unresolved issues and directions for future research

Artale²,

et al. 2014

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Abstract. This paper is the outcome of a workshop held in Rome in November 2011 on the occasion of the 25th anniversary of the POEM (Physical Oceanography of the Eastern Mediterranean) program. In the workshop discussions, a number of unresolved issues were identified for the physical and biogeochemical properties of the Mediterranean Sea as a whole, i.e., comprising the Western and Eastern sub-basins. Over the successive two years, the related ideas were discussed among the group of scientists who participated in the workshop and who have contributed to the writing of this paper.Three major topics were identified, each of them being the object of a section divided into a number of different subsections, each addressing a specific physical, chemical or biological issue:1. Assessment of basin-wide physical/biochemical properties, of their variability and interactions.2. Relative importance of external forcing functions (wind stress, heat/moisture fluxes, forcing through straits) vs. internal variability.3. Shelf/deep sea interactions and exchanges of physical/biogeochemical properties and how they affect the sub-basin circulation and property distribution.Furthermore, a number of unresolved scientific/methodological issues were also identified and are reported in each sub-section after a short discussion of the present knowledge. They represent the collegial consensus of the scientists contributing to the paper. Naturally, the unresolved issues presented here constitute the choice of the authors and therefore they may not be exhaustive and/or complete. The overall goal is to stimulate a broader interdisciplinary discussion among the scientists of the Mediterranean oceanographic community, leading to enhanced collaborative efforts and exciting future discoveries.

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Section: Discussionmentioning

confidence: 99%

Physical forcing and physical/biochemical variability of the Mediterranean Sea: a review of unresolved issues and directions for future research

Artale²,

et al. 2014

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“…They incorporated an arbitrary functional dependence into (7) so as to express energy leakage from turbulence to internal waves. However, their formulation was criticized by Kantha and Clayson (2007), so that was not adopted here.…”

Section: Theoretical Scaling Of G In Terms Of R Otmentioning

confidence: 99%

Observed Variations in Turbulent Mixing Efficiency in the Deep Ocean

Ijichi

Hibiya

2018

Journal of Physical Oceanography

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Recent progress in direct numerical simulations (DNSs) of stratified turbulent flows has led to increasing attention to the validity of the constancy of the dissipation flux coefficient Γ in the Osborn’s eddy diffusivity model. Motivated by lack of observational estimates of Γ, particularly under weakly stratified deep-ocean conditions, this study estimates Γ using deep microstructure profiles collected in various regions of the North Pacific and Southern Oceans. It is shown that Γ is not constant but varies significantly with the Ozmidov/Thorpe scale ratio ROT in a fashion similar to that obtained by previous DNS studies. Efficient mixing events with Γ ~ O(1) and ROT ~ O(0.1) tend to be frequently observed in the deep ocean (i.e., weak stratification), while moderate mixing events with Γ ~ O(0.1) and ROT ~ O(1) tend to be observed in the upper ocean (i.e., strong stratification). The observed negative relationship between Γ and ROT is consistent with a simple scaling that can be derived from classical turbulence theories. In contrast, the observed results exhibit no definite relationships between Γ and the buoyancy Reynolds number Reb, although Reb has long been thought to be another key parameter that controls Γ.

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“…We use a fundamental macroscopic argument by Tennekes [1989]. It has first been cast into mathematical form by Baumert andPeters [2000, 2004] and carefully discussed by Kantha [2004Kantha [ , 2005, by Kantha et al [2005] and by Kantha and Clayson [2007]. Tennekes hypothesized that, in a neutrally stratified homogeneous shear flow, an energycontaining turbulent length scale, L, cannot, on dimensional grounds, depend on the ambient shear.…”

Section: Tke and Vorticity Generation By Mean-flow Shearmentioning

confidence: 99%

Universal equations and constants of turbulent motion

Baumert¹

2013

Phys. Scr.

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Abstract. This paper presents a parameter-free theory of shear-generated turbulence at asymptotically high Reynolds numbers in incompressible fluids. It is based on a two-fluids concept. Both components are materially identical and inviscid. The first component is an ensemble of quasi-rigid dipole-vortex tubes (vortex filaments, excitations) as quasiparticles in chaotic motion. The second is a superfluid performing evasive motions between the tubes. The local dipole motions follow Helmholtz' law. The vortex radii scale with the energy-containing length scale. Collisions between quasiparticles lead either to annihilation (likewise rotation, turbulent dissipation) or to scattering (counterrotation, turbulent diffusion). There are analogies with birth and death processes of population dynamics and their master equations and with Landau's two-flluid theory of liequid Helium. For free homogeneous decay the theory predicts the TKE to follow t −1 . With an adiabatic wall condition it predicts the logarithmic law with von Kármán's constant as 1/ √ 2 π = 0.399. Likewise rotating couples form dissipative patches almost at rest (→ intermittency) wherein under local quasi-steady conditions the spectrum evolves into an "Apollonian gear" as discussed first by Herrmann [1990]. Dissipation happens exclusively at scale zero and at finite scales this system is frictionless and reminds of Prigogine's (1947) law of minimum (here: zero) entropy production. The theory predicts further the prefactor of the 3D-wavenumber spectrum (a Kolmogorov constant) as 1 3 (4 π) 2/3 = 1.802, well within the scatter range of observational, experimental and DNS results.

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On leakage of energy from turbulence to internal waves in the oceanic mixed layer

Cited by 7 publications

References 31 publications

Physical forcing and physical/biochemical variability of the Mediterranean Sea: a review of unresolved issues and directions for future research

Physical forcing and physical/biochemical variability of the Mediterranean Sea: a review of unresolved issues and directions for future research

Observed Variations in Turbulent Mixing Efficiency in the Deep Ocean

Universal equations and constants of turbulent motion

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