Mixing improvement in a resonantly pulsed, confined jet

A resonant entrainment phenomenon associated with a confined, pulsed jet flow is reported, and a method of enhancing entrainment and mixing rates of jets using confinement and pulsing is described. It is shown that a confined jet exhibits excellent resonant entrainment behavior when pulsed at frequencies coinciding with the organ-pipe frequencies of the confining tube. Flow-visualization experiments are conducted using a methane flame and smoke injection, and it is found that the diameter of the confinement tube must be larger than the diameter of the primary jet orifice for the phenomenon to occur.