On dissipation time scales of the basic second-order moments: the effect on the Energy and Flux-Budget (EFB) turbulence closure for stably stratified turbulence
The dissipation rates of the basic turbulent second-order moments are the key parameters controlling turbulence energetics and spectra, turbulent fluxes of momentum and heat, and playing a vital role in turbulence modelling. In this paper, we use the results of Direct Numerical Simulations (DNS) to...
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Main Authors | , , , , |
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Format | Journal Article |
Language | English |
Published |
11.09.2023
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Subjects | |
Online Access | Get full text |
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Summary: | The dissipation rates of the basic turbulent second-order moments are the key
parameters controlling turbulence energetics and spectra, turbulent fluxes of
momentum and heat, and playing a vital role in turbulence modelling. In this
paper, we use the results of Direct Numerical Simulations (DNS) to evaluate
dissipation rates of the basic turbulent second-order moments and revise the
energy and flux-budget turbulence closure model for stably stratified
turbulence. We delve into the theoretical implications of this approach and
substantiate our closure hypotheses through DNS data. We also show why the
concept of down-gradient turbulent transport becomes incomplete when applied to
the vertical turbulent flux of potential temperature under very stable
stratification. We reveal essential feedback between turbulent kinetic energy,
the vertical flux of buoyancy and turbulent potential energy, which is
responsible for maintaining shear-produced stably stratified turbulence up to
extreme static stability. |
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DOI: | 10.48550/arxiv.2309.05869 |