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Forced Stratified Turbulence: Successive Transitions with Reynolds Number

Jean-Philippe Laval·James C. McWilliams
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Abstract

Numerical simulations are made for forced turbulence at a sequence of increasing values of Reynolds number, R, keeping fixed a strongly stable, volume-mean density stratification. At smaller values of R, the turbulent velocity is mainly horizontal, and the momentum balance is approximately cyclostrophic and hydrostatic. This is a regime dominated by so-called pancake vortices, with only a weak excitation of internal gravity waves and large values of the local Richardson number, Ri, everywhere. At higher values of R there are successive transitions to (a) overturning motions with local reversals in the density stratification and small or negative values of Ri; (b) growth of a horizontally uniform vertical shear flow component; and (c) growth of a large-scale vertical flow component. Throughout these transitions, pancake vortices continue to dominate the large-scale part of the turbulence, and the gravity wave component remains weak except at small scales.

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Jean-Philippe Laval, James C. McWilliams. 2003-04-22. Forced Stratified Turbulence: Successive Transitions with Reynolds Number. https://doi.org/10.1103/physreve.68.036308

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