This thesis deals with the flow characteristics of a round jet subject to periodic exitation at the upstream. The method of exitation is acoustic plane wave which has a frequency. Velocity measurement and flow visualization are performed by hot wire anemometer and schlieren technique.
The schlieren photographs synchronized with the signal of hot wire anemometer reveal the vortex ring affected upon velocity field due to acoustic excitation.
In near field of jet the flow is very organized and becomes periodic by the vortex ring motion of which shedding frequency is the same as that of the acoustic wave.
In excited flow field, the vortex ring is generated repeatedly and dissipated by interaction between periodic motion and background turbulence.
Momentum transfer in radial direction and the entrainment rate to axial direction are increased by large coherent motion which might be originated by acoustic exitation.