周囲に逆流を伴う円形噴流に形成されるサイドジェット

抄録

When a low density fluid, such as hot air and helium gas, is discharged from a round nozzle, side jets are generated in the initial region of the jet. These radial ejections of the jet fluid are called side jets. It is thought that the side jets are generated by self-excited oscillations in the jet column. The self-excited oscillations are caused by the local absolute instability. We think that the absolute instability is generated in the jet column by a feedback effect generated by an external counter flow. It was confirmed that the side jet is formed in a round jet with an external counter flow, using flow visualization by a planar laser Mie scattering.