Affiliations: Chair of Maritime Safety Technology, Japan Coast Guard
Academy, 5-1 Wakaba-cho, Kure, Hiroshima 737-8512, Japan. Tel:
+81-823-21-4961/Fax: +81-823-20-0087, E-mail: shimada@jcga.ac.jp | Faculty of Engineering, Ehime University, 3
Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan | Chiba Polytechnic College, 221-20 Namiki-cho, Narita,
Chiba 286-0045, Japan | Graduate School of Engineering, Hiroshima University,
1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan | Shibaura Institute of Technology, 3-9-14 Shibaura,
Minato-ku, Tokyo 108-8548, Japan
Abstract: This paper is concerned with an experimental investigation on plane
submerged water jets discharged into quiescent water in an open channel. Flows
are visualized by using hydrogen bubbles, solid particles and dye. The results
show that the jets attaching to the water surface by the Coanda effect are
classified into six types according to their behavior after issuing from the
nozzle, and that the self-induced vibration of the jet, which is one of six
flow patterns, occurs under the condition of the reduced Froude number
Fr*≒ 0.7 ∼1.0. An additional analysis of the photographs reveals
that the self-induced vibration of the jet is caused by attachment of the jet
to the water surface and the ensuing bifurcation of the jet at an attachment
point, and that the frequency of vibration is independent of the water level.
Keywords: Flow Visualization, Hydraulic Jump, Self-Induced Vibration, Water Jet
