Spatial Development Process of a Round Jet which Locally Excited from One Direction

Abstract

Vortex rings are periodically formed in the initial region of a round jet. Many researchers and engineers have done studies focusing on the vortex structure for clarification and control of the jet. It is necessary to locally give the jet the disturbance to control the local structure of the jet. In this study, a round jet is locally excited by a local sound wave radiated from a loudspeaker inputting a sine wave. it is found that the acoustic excitation produces azimuthod deformation of vortex ring. So that the spatial development is different from that of an unexcited jet. The relationship between the input signal to the speaker and the spatial structure of the jet was investigated using visualization using PLMS.