Skip to main content Accessibility help

We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.

Close cookie message
×
Home
  • Home

Refine search

Refine search

Access:
Content type:
Publication date:
Apply
Subject: Show more
Journals Show more
Publishers: Show more
Societies Show more
Series: Show more
Collections: Show more

Actions for selected content:

Select all | Deselect all
  • View selected items
  • Export citations
  • Download PDF (zip)
  • Send to Kindle
  • Send to Dropbox
  • Send to Google Drive

Save Search

You can save your searches here and later view and run them again in "My saved searches".

Please provide a title, maximum of 40 characters.
Cancel
×

53 results

Page 1 of 3

  • Statistical state dynamics analysis of buoyancy layer formation via the Phillips mechanism in two-dimensional stratified turbulence
  • Joseph G. Fitzgerald, Brian F. Farrell
  • Journal: Journal of Fluid Mechanics / Volume 864 / 10 April 2019
  • Published online by Cambridge University Press: 11 February 2019, R3
  • Print publication: 10 April 2019
  • View abstract

    Horizontal density layers are commonly observed in stratified turbulence. Recent work (e.g. Taylor & Zhou, J. Fluid Mech., vol. 823, 2017, R5) has reinvigorated interest in the Phillips instability (PI), by which density layers form via negative diffusion if the turbulent buoyancy flux weakens as stratification increases. Theoretical understanding of PI is incomplete, in part because it remains unclear whether and by what mechanism the flux-gradient relationship for a given example of turbulence has the required negative-diffusion property. Furthermore, the difficulty of analysing the flux-gradient relation in evolving turbulence obscures the operating mechanism when layering is observed. These considerations motivate the search for an example of PI that can be analysed clearly. Here PI is shown to occur in two-dimensional Boussinesq sheared stratified turbulence maintained by stochastic excitation. PI is analysed using the second-order S3T closure of statistical state dynamics, in which the dynamics is written directly for statistical variables of the turbulence. The predictions of S3T are verified using nonlinear simulations. This analysis provides theoretical underpinning of PI based on the fundamental equations of motion that complements previous analyses based on phenomenological models of turbulence.

  • Statistical state dynamics of vertically sheared horizontal flows in two-dimensional stratified turbulence
  • Joseph G. Fitzgerald, Brian F. Farrell
  • Journal: Journal of Fluid Mechanics / Volume 854 / 10 November 2018
  • Published online by Cambridge University Press: 12 September 2018, pp. 544-590
  • Print publication: 10 November 2018
  • View abstract

    Simulations of strongly stratified turbulence often exhibit coherent large-scale structures called vertically sheared horizontal flows (VSHFs). VSHFs emerge in both two-dimensional (2D) and three-dimensional (3D) stratified turbulence with similar vertical structure. The mechanism responsible for VSHF formation is not fully understood. In this work, the formation and equilibration of VSHFs in a 2D Boussinesq model of stratified turbulence is studied using statistical state dynamics (SSD). In SSD, equations of motion are expressed directly in the statistical variables of the turbulent state. Restriction to 2D turbulence facilitates application of an analytically and computationally attractive implementation of SSD referred to as S3T, in which the SSD is expressed by coupling the equation for the horizontal mean structure with the equation for the ensemble mean perturbation covariance. This second-order SSD produces accurate statistics, through second order, when compared with fully nonlinear simulations. In particular, S3T captures the spontaneous emergence of the VSHF and associated density layers seen in simulations of turbulence maintained by homogeneous large-scale stochastic excitation. An advantage of the S3T system is that the VSHF formation mechanism, which is wave–mean flow interaction between the emergent VSHF and the stochastically excited large-scale gravity waves, is analytically understood in the S3T system. Comparison with fully nonlinear simulations verifies that S3T solutions accurately predict the scale selection, dependence on stochastic excitation strength, and nonlinear equilibrium structure of the VSHF. These results constitute a theory for VSHF formation applicable to interpreting simulations and observations of geophysical examples of turbulent jets such as the ocean’s equatorial deep jets.

Habeas Corpus in International Law
  • Habeas Corpus in International Law
  • Brian R. Farrell
  • Published online: 15 December 2016
  • Print publication: 17 November 2016
  • View description
    Habeas Corpus in International Law is the first comprehensive examination of this subject. It looks at the location, scope, and significance of the right to a judicial determination of the legality of one's detention as guaranteed by international and regional human rights instruments. First, it examines the history of habeas corpus and its place in human rights treaties, providing a useful resource for understanding the status and application of this internationally-protected right. The book continues by identifying and analyzing the primary challenges to habeas corpus, in particular its applicability during armed conflict, the possibility of derogation, and its extraterritorial application and procedural shortcomings. The book next addresses the significance of habeas corpus guarantees not just in protecting personal liberty, but in promoting the international rule of law by serving as a unique check on executive action. Finally, it offers suggestions on how this right might be strengthened.

Page 1 of 3