Turbulent fluxes in stably stratified boundary layers

L’vov, Victor S.; Procaccia, Itamar; Rudenko, Oleksii

doi:10.1088/0031-8949/2008/t132/014010

Cited by 9 publications

(5 citation statements)

References 27 publications

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“…These results point to the absence of the critical gradient Richardson number, Ri cr [ Galperin et al , 2007], a conclusion of fundamental significance with important implications for numerical modeling of geophysical and planetary systems. The absence of Ri cr has recently been adopted in Reynolds stress modeling [ Zilitinkevich et al , 2007; Canuto et al , 2008; L'vov et al , 2008; Violeau , 2009].…”

Section: Diffusion In Stably Stratified Flowsmentioning

confidence: 99%

Transport of momentum and scalar in turbulent flows with anisotropic dispersive waves

Sukoriansky¹,

Dikovskaya²,

Galperin³

2009

Geophysical Research Letters

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Most geophysical flows encompass turbulence and internal and/or Rossby waves. We demonstrate that these two different classes of waves cause remarkably similar anomalies in the turbulent transport. While all scales in both types of flows contribute to the momentum diffusion, the vertical (diapycnal) scalar diffusion in stratified flows and lateral diffusion in β‐plane turbulence can be carried out only by turbulent eddies whose size is smaller than the thresholds of turbulence anisotropization. Beyond these thresholds, both flows become dominated by waves that provide no contribution to the scalar diffusion. Stably stratified flows exhibit enhanced isopycnal diffusion of both momentum and scalar. These results shed new light on the Osborn mixing model, diapycnal and isopycnal viscosity and diffusivity, absence of the critical gradient Richardson number, and large scale meridional transport.

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Section: Diffusion In Stably Stratified Flowsmentioning

confidence: 99%

Transport of momentum and scalar in turbulent flows with anisotropic dispersive waves

Sukoriansky¹,

Dikovskaya²,

Galperin³

2009

Geophysical Research Letters

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“…It does not imply any critical Ri in the traditional sense (as the boundary between turbulent and laminar regimes) but discloses, just around Ri ~ 0.2-0.3, quite sharp transition between the two turbulent regimes of principally different nature: strong turbulence at small Ri and weak turbulence at large Ri. Following the EFB closure (Elperin et al, 2005;Zilitinkevich et al, 2007), other recently published turbulent closure models (Mauritsen et al 2007, Canuto et al, 2008, L'vov et al 2008, Sukoriansky and Galperin, 2008…”

Section: Introductionmentioning

confidence: 99%

A Hierarchy of Energy- and Flux-Budget (EFB) Turbulence Closure Models for Stably-Stratified Geophysical Flows

Zilitinkevich

Elperin

Kleeorin

et al. 2012

Boundary-Layer Meteorol

155

173

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In this paper we advance physical background of the energy-and flux-budget turbulence closure based on the budget equations for the turbulent kinetic and potential energies and turbulent fluxes of momentum and buoyancy, and a new relaxation equation for the turbulent dissipation time-scale. The closure is designed for stratified geophysical flows from neutral to very stable and accounts for the Earth rotation. In accordance to modern experimental evidence, the closure implies maintaining of turbulence by the velocity shear at any gradient Richardson number Ri, and distinguishes between the two principally different regimes: "strong turbulence" at Ri << 1 typical of boundary-layer flows and characterised by the practically constant turbulent Prandtl number T r P ; and "weak turbulence" at Ri > 1 typical of the free atmosphere or deep ocean, where T r P asymptotically linearly increases with increasing Ri (which implies very strong suppression of the heat transfer compared to the momentum transfer). For use in different applications, the closure is formulated at different levels of complexity, from the local algebraic model relevant to the steady-state regime of turbulence to a hierarchy of non-local closures including simpler down-gradient models, presented in terms of the eddy-viscosity and eddy-conductivity, and general non-gradient model based on prognostic equations for all basic parameters of turbulence including turbulent fluxes. Keywords:Boundary

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“…The EFB theory have been verified against scarce data from the atmospheric experiments, direct numerical simulations (DNS), large-eddy simulations (LES) and laboratory experiments relevant to the steady state turbulence regime. Following the EFB closure, other turbulent closure models also do not imply a critical Richardson number [35][36][37][38][39][40][41][42][43][44].…”

Section: Introductionmentioning

confidence: 99%

The energy- and flux budget theory for surface layers in atmospheric convective and stably stratified turbulence

Rogachevskii¹,

Kleeorin²,

Zilitinkevich³

2021

Preprint

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The Energy-and Flux Budget (EFB) turbulence closure theory for the atmospheric surface layers in convective and stably stratified turbulence has been developed using budget equations for turbulent energies and fluxes in the Boussinesq approximation. In the lower part of the surface layer in the atmospheric convective boundary layer (CBL), the rate of turbulence production of the turbulent kinetic energy (TKE) caused by the mean-flow surface shear and the shear of selforganised coherent structures is much larger than that caused by the buoyancy, which results in three-dimensional turbulence of very complex nature. In the upper part of the surface layer, the rate of turbulence production of TKE due to the shear is much smaller than that caused by the buoyancy, which causes unusual strongly anisotropic buoyancy-driven turbulence. Considering the applications of the obtained results to the atmospheric convective and stably stratified boundarylayer turbulence, the theoretical relationships potentially useful in modelling applications have been derived. In particular, the developed unified theory for the surface layers in turbulent convection and stably stratified turbulence allows us to determine the vertical profiles for all turbulent characteristics, including TKE, the intensity of turbulent potential temperature fluctuations, the vertical turbulent fluxes of momentum and buoyancy (proportional to potential temperature), the integral turbulence scale, the turbulent anisotropy, the turbulent Prandtl number and the flux Richardson number. This theory also yields the profiles of the mean velocity and mean potential temperature.

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Turbulent fluxes in stably stratified boundary layers

Cited by 9 publications

References 27 publications

Transport of momentum and scalar in turbulent flows with anisotropic dispersive waves

Transport of momentum and scalar in turbulent flows with anisotropic dispersive waves

A Hierarchy of Energy- and Flux-Budget (EFB) Turbulence Closure Models for Stably-Stratified Geophysical Flows

The energy- and flux budget theory for surface layers in atmospheric convective and stably stratified turbulence

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