Jets are important in many practical applications, e.g..related to combustion.propulsion.mixing.and aeroacoustic.As one of the generic flow of fluid mechanics, jets have been of scientific interest for over 100 years [1].The round jet results when fluid is emitted, with a given initial momentum.out of a circular orifice into a large space.At sufficiently high Reynolds numbers this jet will be turbulent.The stability properties of the flow play a fundamental role in the transition to turbulence and the formation of coherent vortex structures in a turbulent fluid [2.3].