Affiliations: Department of Mechanical Systems Engineering, School
of Engineering, Kyushu Tokai University 9-1-1 Toroku, Kumamoto, Japan. E-mail:
[email protected] | Industrial Techno-Research Institute, Kyushu Tokai
University | Department of Information Systems Engineering, Kyushu
Tokai University | Graduate School of Engineering, Kyushu Tokai
University
Abstract: The standing wave in the near field of the screech jet exhausted
from a nozzle with a hard plate works on the jet flow as the forcing wave by
the location of a reflecting plate, and then jet flow is considered to be
changed. Moreover, the reflector location from the nozzle changes the sound
pressure contours of the near field. Intensity maps of the screech tone which
indicate the propagation to the jet axial direction or the radial direction of
the jet by the presence of the reflector plate have not been explored. In the
present paper, acoustic characteristics in the near field of the screech tone
with the reflecting plate are studied using an optical wave microphone, which
can measure the sound propagating for both vertical and horizontal directions
to the jet axis. As a result, the standing wave in the near field of the
screech jet with the reflector has two types: One is the standing wave between
the hydrodynamic pressure fluctuation propagating jet downstream and the sound
pressure propagating upstream, and the other is the standing wave by the
difference between the wavelength of the sound wave and the wavelength at the
place close to the jet.
