EXPERIMENTAL DETERMINATION OF THE THREE-DIMENSIONAL VORTICITY FIELD IN THE BOUNDARY-LAYER TRANSITION PROCESS.

D. R. Williams, Hermann F Fasel, F. R. Hama

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

The vortex loop observed in flow-visualization studies of boundary-layer transition has been investigated by mapping the instantaneous velocity and vorticity fields. All three velocity components have been measured with hot-film anemometers at numerous grid points in a measuring volume centered on the location where the vortex loop appears in flow-visualization studies. The instantaneous vorticity field has been computed from the velocity field, and the vortex loop is revealed in the longitudinal component of vorticity. The loop propagates downstream at approximately the primary disturbance wavespeed. The fluid in the outer part of the boundary layer travels faster, and flows over the loop. This forms the inflexional high-shear layer, which breaks down into the hairpin vortices. The magnitude of the vorticity in the high-shear layer is actually about three times larger than that in the loop. These two regions of vorticity are distinguished by the direction of the instantaneous vorticity vectors.

Original languageEnglish (US)
Pages (from-to)179-203
Number of pages25
JournalJournal of Fluid Mechanics
Volume149
StatePublished - Dec 1984
Externally publishedYes

Fingerprint

boundary layer transition
Vorticity
vorticity
Boundary layers
Vortex flow
flow visualization
shear layers
vortices
Flow visualization
hot-film anemometers
velocity distribution
horseshoe vortices
Anemometers
travel
boundary layers
disturbances
breakdown
grids
Fluids
fluids

ASJC Scopus subject areas

  • Computational Mechanics
  • Mechanics of Materials
  • Physics and Astronomy(all)
  • Condensed Matter Physics

Cite this

EXPERIMENTAL DETERMINATION OF THE THREE-DIMENSIONAL VORTICITY FIELD IN THE BOUNDARY-LAYER TRANSITION PROCESS. / Williams, D. R.; Fasel, Hermann F; Hama, F. R.

In: Journal of Fluid Mechanics, Vol. 149, 12.1984, p. 179-203.

Research output: Contribution to journalArticle

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