Predicting the collapse of turbulence in stably stratified boundary layers

Research output: Contribution to journalArticleAcademicpeer-review

57 Citations (Scopus)

Abstract

The collapse of turbulence in a plane channel flow is studied, as a simple analogy of stably stratified atmospheric flow. Turbulence is parameterized by first-order closure and the surface heat flux is prescribed, together with the wind speed and temperature at the model top. To study the collapse phenomenon both numerical simulations and linear stability analysis are used. The stability analysis is nonclassical in a sense that the stability of a parameterized set of equations of a turbulent flow is analyzed instead of a particular laminar flow solution. The analytical theory predicts a collapse of turbulence when a certain critical value of the stability parameter ¿/L (typically O(0.5¿1)) is exceeded, with ¿ the depth of the channel and L the Obukhov length. The exact critical value depends on channel roughness to depth ratio z 0/¿. The analytical predictions are validated by the numerical simulations, and good agreement is found. As such, for the flow configuration considered, the present framework provides both a tool and a physical explanation for the collapse phenomenon.
Original languageEnglish
Pages (from-to)251-274
JournalFlow, Turbulence and Combustion
Volume79
Issue number3
DOIs
Publication statusPublished - 2007

Keywords

  • temperature-fluctuation method
  • intermittent turbulence
  • part ii
  • cases-99
  • land
  • oscillations
  • stability
  • dynamics
  • surface
  • fluxes

Fingerprint Dive into the research topics of 'Predicting the collapse of turbulence in stably stratified boundary layers'. Together they form a unique fingerprint.

Cite this