On the periodicity of atmospheric von Kármán vortex streets

Christopher G. Nunalee, Sukanta Basu

Research output: Contribution to journalArticleScientificpeer-review

17 Citations (Scopus)

Abstract

For over 100 years, laboratory-scale von Kármán vortex streets (VKVSs) have been one of the most studied phenomena within the field of fluid dynamics. During this period, countless publications have highlighted a number of interesting underpinnings of VKVSs; nevertheless, a universal equation for the vortex shedding frequency ( {Mathematical expression}) has yet to be identified. In this study, we have investigated {Mathematical expression} for mesoscale atmospheric VKVSs and some of its dependencies through the use of realistic numerical simulations. We find that vortex shedding frequency associated with mountainous islands, generally demonstrates an inverse relationship to cross-stream obstacle length ( {Mathematical expression}) at the thermal inversion height of the atmospheric boundary layer. As a secondary motive, we attempt to quantify the relationship between {Mathematical expression} and {Mathematical expression} for atmospheric VKVSs in the context of the popular Strouhal number ( {Mathematical expression})-Reynolds number ( {Mathematical expression}) similarity theory developed through laboratory experimentation. By employing numerical simulation to document the {Mathematical expression} relationship of mesoscale atmospheric VKVSs (i.e., in the extremely high {Mathematical expression} regime) we present insight into an extended regime of the similarity theory which has been neglected in the past. In essence, we observe mesoscale VKVSs demonstrating a consistent {Mathematical expression} range of 0.15-0.22 while varying {Mathematical expression} (i.e, effectively varying {Mathematical expression}).

Original languageEnglish
Pages (from-to)1-21
Number of pages21
JournalEnvironmental Fluid Mechanics
DOIs
Publication statusAccepted/In press - 2014
Externally publishedYes

Keywords

  • Island wakes
  • Marine boundary layer
  • Stably stratified flows
  • Strouhal number
  • Von Kármán vortex street

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