Double-helical pairing in plane mixing layers

Double-helical pairing is identified in the second vortex pairing of a spanwise-unforced plane mixing layer. Phase-locked measurements using two-dimensional (2D) periodic acoustic excitation reveal that as the rollers of the second pairing approach each other, three-dimensional (3D) modes become amp...

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Bibliographic Details
Published inPhysics of fluids (1994) Vol. 11; no. 6; pp. 1691 - 1693
Main Authors Estevadeordal, Jordi, Kleis, Stanley J.
Format Journal Article
LanguageEnglish
Published 01.06.1999
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Summary:Double-helical pairing is identified in the second vortex pairing of a spanwise-unforced plane mixing layer. Phase-locked measurements using two-dimensional (2D) periodic acoustic excitation reveal that as the rollers of the second pairing approach each other, three-dimensional (3D) modes become amplified in each roller. Rollers then revolve around each other, forming a double helix with spanwise wavelength on the order of the streamwise lengthscale. Some spanwise areas exhibit a more advanced pairing stage than others, producing “branched” vortex patterns.
ISSN:1070-6631
1089-7666
DOI:10.1063/1.870033