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Nonlinear evolution of linear optimal perturbations of strongly stratified shear layers
(Cambridge University PressJournal of Fluid Mechanics, 2017-08-25)
The Miles-Howard theorem states that a necessary condition for normal-mode instability in parallel, inviscid, steady stratified shear flows is that the minimum gradient Richardson number, $Ri_{g,min}$, is less than 1/4 ...
Testing linear marginal stability in stratified shear layers
We use two-dimensional direct numerical simulations of Boussinesq stratified shear layers to investigate the influence of the minimum gradient Richardson number Rim on the early time evolution of Kelvin–Helmholtz instability ...
A new method for isolating turbulent states in transitional stratified plane Couette flow
(Cambridge University PressJournal of Fluid Mechanics, 2016-10-26)
We present a new adaptive control strategy to isolate and stabilize turbulent states in transitional, stably stratified plane Couette flow in which the gravitational acceleration (non-dimensionalized as the bulk Richardson ...
Robust identification of dynamically distinct regions in stratified turbulence
(Cambridge University PressJournal of Fluid Mechanics, 2016-10-18)
We present a new robust method for identifying three dynamically distinct regions in a stratified turbulent flow, which we characterise as quiescent flow, intermittent layers and turbulent patches. The method uses the ...
Self-similar mixing in stratified plane Couette flow for varying Prandtl number
(Cambridge University PressJournal of Fluid Mechanics, 2017-06-10)
We investigate fully developed turbulence in stratified plane Couette flows using direct numerical simulations similar to those reported by Deusebio et al. (J. Fluid Mech., vol. 781, 2015, pp. 298-329) expanding the range ...
Diapycnal mixing in layered stratified plane Couette flow quantified in a tracer-based coordinate
(Cambridge University PressJournal of Fluid Mechanics, 2017-07)
The mixing properties of statically stable density interfaces subject to imposed vertical shear are studied using direct numerical simulations of stratified plane Couette flow. The simulations are designed to investigate ...