Side-jets formation in a rectangular helium gas jet.

Abstract

It is thought that local absolute instability by jet fluid with low density and Widnall instability of a vortex ring are related with side-jets formation in a round jet with low-density. If the density of the jet fluid is sufficiently lower than that of the ambient fluid, an initial region in a two-dimensional jet becomes locally absolute unstable. Side jets are formed in the rectangular jet as similar to a round jet, when the density of jet fluid is sufficiently lower than that of ambient fluid. Relationship between streamwise vortexes and side-jets is discussed from a result of three-dimensional imaging for the rectangular jet.