Topological studies of circular and elliptic jets in a cross flow

Abstract

An experimental study has been carried on transverse circular and elliptic jets in cross flow to investigate the resultant topological origins and structures. Experiments using parabolic and a??top-hata?? velocity-profiled circular jets showed that the traditionally-held belief that the resultant counter-rotating vortex pair structure was formed by a a??tilting-and-folding of circular vortex ringsa?? mechanism might be better accounted for and explained by a newly proposed flow model utilising vortex loops instead. The new model offers an fresh alternative from another perspective which is able to explain much of the existing experimental observations with little compromise with the physical reality of the flow field. Subsequent detailed studies on elliptic jets in cross flow provided further evidences for and strengthened the new flow model. Significant topological details not reported by previous investigations were made as well, including the apparent heavy dependency of the near-field vortex structures on the elliptic jet orientation.