Resolving the Paradox of Oceanic Large-Scale Balance and Small-Scale Mixing

Marino, Raffaele; Pouquet, A.; Rosenberg, Duane

doi:10.1103/physrevlett.114.114504

Cited by 85 publications

(99 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results demonstrate that the presence of stratification decreases energy transfer between large and sub-filter scales, i.e. both up-and downscale energy transfers are reduced by increasing stratification [29,30]. As seen above for the viscous dissipation rates, the three simulations with largest Re b have similar ϵ ± and ε ± time series, which peak at an earlier time than all the other stratified cases.…”

Section: Energy Transfer In Physical Spacesupporting

confidence: 69%

Backscatter in stratified turbulence

Khani

Waite

2016

European Journal of Mechanics - B/Fluids

View full text Add to dashboard Cite

a b s t r a c tIn this paper, kinetic and potential energy transfers around a spectral test filter scale in direct numerical simulations of decaying stratified turbulence are studied in both physical and spectral domains. It is shown that while the domain-averaged effective subgrid scale energy transfer in physical space is a net downscale cascade, it is actually a combination of large values of downscale and upscale transfer, i.e. forward-and backscatter, in which the forward scatter is slightly dominant. Our results suggest that spectral backscatter in stratified turbulence depends on the buoyancy Reynolds number Re b and the filtering scale ∆ test . When the test filter scale ∆ test is around the dissipation scale L d , transfer spectra show spectral backscatter from sub-filter to intermediate scales, as reported elsewhere. However, we find that this spectral backscatter is due to viscous effects at vertical scales around the test filter. It is also shown that there is a non-local energy transfer from scales larger than the buoyancy scale L b to small scales. The effective turbulent Prandtl number spectra demonstrate that the assumption Pr t ≈ 1 is reasonable for the local energy transfer.

show abstract

Section: Energy Transfer In Physical Spacesupporting

confidence: 69%

Backscatter in stratified turbulence

Khani

Waite

2016

European Journal of Mechanics - B/Fluids

View full text Add to dashboard Cite

show abstract

“…Indeed, it is known that there is a critical Rossby number ≈ 0.1 − 0.2 above which the influence of rotation is greatly diminished, and in the forced case the inverse cascade of energy disappears. This point was also observed in [17] when expressed in terms of a change of behavior of the relative strength of the inverse and direct energy fluxes for N/f ≈ 7, corresponding to a transition for Ro � 0.45.…”

Section: Framework For the Parametric Studymentioning

confidence: 72%

“…In fact, it is known that the direct cascade of energy to small scales is due in part to nonlinear triadic interactions between eddies and waves [12][13][14][15], but that waves and vortices exchange less energy in the presence of rotation than for purely stratified flows [12]. Moreover, the total energy is now being transferred both to the large and to the small scales with a dual constant-flux energy cascade [16,17], as also recently observed for the ocean using sea-surface heights measurements [18,19]. Thus, this wave-vortex transition is quite a general feature of atmospheric and oceanic flows although there is no clear consensus as to what governs the scale at which it occurs.…”

Section: Introductionmentioning

confidence: 99%

Interplay of waves and eddies in rotating stratified turbulence and the link with kinetic-potential energy partition

Marino¹,

Rosenberg²,

Herbert³

et al. 2015

EPL

View full text Add to dashboard Cite

The interplay between waves and eddies in stably stratified rotating flows is investigated by means of world-class direct numerical simulations using up to 3072 3 grid points. Strikingly, we find that the shift from vortex to wave dominated dynamics occurs at a wavenumber kR which does not depend on Reynolds number, suggesting that partition of energy between wave and vortical modes is not sensitive to the development of turbulence at the smaller scales. We also show that kR is comparable to the wavenumber at which exchanges between kinetic and potential modes stabilize at close to equipartition, emphasizing the role of potential energy, as conjectured in the atmosphere and the oceans. Moreover, kR varies as the inverse of the Froude number as explained by the scaling prediction proposed, consistent with recent observations and modeling of the Mesosphere-Lower Thermosphere and of the ocean.

show abstract

“…Large scale forcing is required as one of our goals will be to identify the role of the waves at small scales, but it will force us to complement the results in these sections with the results in the previous sections where time resolution was not as good, but the inverse cascade ranges were better resolved. To study both ranges separately is a common practice in geophysical fluid dynamics due to constraints in computing power, as only very recently simulations were able to resolve dual cascades in a unique simulation at very high resolution [99]. Figure 5 shows a detail, in the vicinity of the inertial range, of the isotropic energy spectrum E(k) for four 512 3 runs with Ro ≈ 0.2 and varying Fr (and therefore, varying N/f ).…”

Section: Quasi-geostrophic Behaviormentioning

confidence: 99%

Inverse cascades and resonant triads in rotating and stratified turbulence

et al. 2017

Self Cite

View full text Add to dashboard Cite

Kraichnan seminal ideas on inverse cascades yielded new tools to study common phenomena in geophysical turbulent flows. In the atmosphere and the oceans, rotation and stratification result in a flow that can be approximated as two-dimensional at very large scales, but which requires considering three-dimensional effects to fully describe turbulent transport processes and non-linear phenomena. Motions can thus be classified into two classes: fast modes consisting of inertia-gravity waves, and slow quasi-geostrophic modes for which the Coriolis force and horizontal pressure gradients are close to balance. In this paper we review previous results on the strength of the inverse cascade in rotating and stratified flows, and then present new results on the effect of varying the strength of rotation and stratification (measured by the inverse Prandtl ratio N/f , of the Coriolis frequency to the Brunt-Väisäla frequency) on the amplitude of the waves and on the flow quasi-geostrophic behavior. We show that the inverse cascade is more efficient in the range of N/f for which resonant triads do not exist, 1/2 ≤ N/f ≤ 2. We then use the spatio-temporal spectrum to show that in this range slow modes dominate the dynamics, while the strength of the waves (and their relevance in the flow dynamics) is weaker.

show abstract

Resolving the Paradox of Oceanic Large-Scale Balance and Small-Scale Mixing

Cited by 85 publications

References 39 publications

Backscatter in stratified turbulence

Backscatter in stratified turbulence

Interplay of waves and eddies in rotating stratified turbulence and the link with kinetic-potential energy partition

Inverse cascades and resonant triads in rotating and stratified turbulence

Contact Info

Product

Resources

About