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Now showing items 11-20 of 21
Efficiency of turbulent mixing in the abyssal ocean circulation
(American Geophysical UnionGeophysical Research Letters, 2017-07-17)
Turbulent mixing produced by breaking of internal waves plays an important role in setting the patterns of downwelling and upwelling of deep dense waters and thereby helps sustain the global deep ocean overturning circulation. ...
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 ...
Role of overturns in optimal mixing in stratified mixing layers
(Cambridge University PressJournal of Fluid Mechanics, 2017-09-10)
Turbulent mixing plays a major role in enabling the large scale ocean circulation. The accuracy of mixing rates estimated from observations
depends on our understanding of basic fluid mechanical processes underlying the ...
Adjoint-based optimization of displacement ventilation flow
(ElsevierBuilding and Environment, 2017-11-01)
We demonstrate the use of the ‘Direct-Adjoint-Looping method’ for the identification of optimal buoyancy-driven ventilation flows governed by Boussinesq equations. We use the incompressible Reynolds-averaged Navier-Stokes ...
Designing a more nonlinearly stable laminar flow via boundary manipulation
(Cambridge University PressJournal of Fluid Mechanics, 2013-12-04)
We show how a fully nonlinear variational method can be used to design a more nonlinearly stable laminar shear flow by quantifying the effect of manipulating the boundary conditions of the flow. Using the example of plane ...
Turbulent mixing due to the Holmboe wave instability at high Reynolds number
(Cambridge University PressJournal of Fluid Mechanics, 2016)
We consider numerically the transition to turbulence and associated mixing in stratified shear flows with initial velocity distribution $\bar U$(z, 0)e$_{x}$ = U$_{0}$e$_{x}$ tanh(z/d) and initial density distribution $\bar ...
Coherent structures in interacting vortex rings
(American Physical SocietyPhysical Review Fluids, 2017-02-21)
We investigate experimentally the nonlinear structures that develop from interacting vortex rings induced by a sinusoidally oscillating ellipsoidal disk in fluid at rest. We vary the scaled amplitude or Keulegan-Carpenter ...
Irreversible mixing by unstable periodic orbits in buoyancy dominated stratified turbulence
(Cambridge University PressJournal of Fluid Mechanics, 2017-10-26)
We consider turbulence driven by a large-scale horizontal shear in Kolmogorov flow
(i.e. with sinusoidal body forcing) and a background linear stable strati cation with buoyancy frequency $N^2_B$ imposed in the third, ...
Layer formation in horizontally forced stratified turbulence: Connecting exact coherent structures to linear instabilities
(Journal of Fluid Mechanics, 2017-12-10)
© 2017 Cambridge University Press. We consider turbulence in a stratified 'Kolmogorov' flow, driven by horizontal shear in the form of sinusoidal body forcing in the presence of an imposed background linear stable ...