Active management of naturally separated flow over a solid surface. Part 1. The forced reattachment process

A. Darabi, I. Wygnanski

Research output: Contribution to journalArticle

132 Scopus citations

Abstract

The forced reattachment of flow to an inclined flat surface, simulating a simple flap, was investigated experimentally. The transition from a separated to an attached state of the flow was initiated by an abrupt change in the frequency and the amplitude of periodic perturbations emanating from a slot at the flap shoulder. The excitation parameters determined the total duration of the reattachment process. Minimum reattachment time occurred at an optimal excitation frequency of Fopt+ ≈ 1.5, which was independent of amplitude and flap inclination. The control over the process was achieved by enhancing large spanwise vortices in the flow. Spatial amplification of consecutive vortices induces mean transport of fluid away from the flap surface which causes the main stream to reattach. The time scales of the excitation are at least an order of magnitude smaller than the typical reattachment times.

Original languageEnglish (US)
Pages (from-to)105-129
Number of pages25
JournalJournal of Fluid Mechanics
Issue number510
DOIs
StatePublished - Jul 10 2004

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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