A Study of the Vortical Structures of Noncircular Jets

Kuniaki Toyoda, Fazle Hussain

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12 Scopus citations


Noncircular jets issuing from square, triangular and rectangular orifices are investigated using a flow visualization technique employing laser-fluorescent dye, and controlling vortex evolutions under excitation. In square, triangular, and 2:1 rectangular jets, the corner regions of noncircular vortical structures undergo severe deformation due to self-induced velocity, resulting in the switchover of the geometric axes. The deformation of vortices in a 4:1 rectangular jet is so severe that the major-axis sides come close to each other, collide, and crosslink, and the original single vortex ring bifurcates to two small vortices via the so-called cut-and-connect process. Interactions of two noncircular vortices are affected by self- and mutually-induced velocities, and produce partial merging, vortex stretching, and splitting to small vortices. These results suggest that noncircular jets are very effective in the enhancement of mixing.

Original languageEnglish
Pages (from-to)1542-1545
Number of pages4
JournalTransactions of the Japan Society of Mechanical Engineers Series B
Issue number514
StatePublished - 1989


  • Coherent Structures
  • Flow Visualization
  • Jet
  • Turbulent Flow
  • Vortex


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