Abstract
When a low density gas compared with the ambient gas is issued from a round nozzle, radial ejections of jet fluid are generated at near the nozzle exit. This phenomenon is called a side-jet. It is thought that the density ratio between the jet fluid and the ambient fluid, the jet Re number, and the momentum thickness at the nozzle exit are conditions for the side-jet formation. The momentum thicknesses and shear stress in variable density jets were measured using a hot-wire probe and a hot-wire concentration probe. The side-jet formation was observed by flow visualization. The condition for the side-jet formation can be displayed in the domain between the density ratio and the non-dimensional momentum thickness.
