Characteristics of Supersonic Water Jet in Sea Water
The characteristics of supersonic water jet injected in sea water is preliminarily described in this research. The main
focus is to compare the dynamic behaviors of the jet injected in sea water, water and ambient air. The supersonic water jets
were generated by impact driven method in a horizontal single-stage power gun being designed and constructed for this study.
The jets were visualized by the shadowgraph technique, and the images were recorded by a high-speed digital video camera.
From the shadowgraph images, the core jet, water vapor bubble, shock wave in sea water and rebound shock wave generated
because of bubble collapse is obviously observed. The maximum averaged velocity of the jet injected in sea water, water and
air were 266.80 m/s, 374.24 m/s and 1,669.03 m/s, respectively. The averaged velocity of jet injected in sea water is much
slower than that in air because hydrodynamic drag is much higher than aerodynamic drag. Since the density of sea water is
higher than that of water, the averaged velocity of jet injected in sea water is lower than that in water. These effect on the
penetration distance of jet injected in sea water being shorter than that in water and air, respectively.
Index Terms - Supersonic water jet, Sea water, Shock wave, Shadowgraph technique.