A study has been made of the behavior of gas jet injected into a two-dimensional mercury bath. The vessel was made of acrylate resins. The sheet of mercury was 0.5cm thick. Nitrogen gas (580-3 300cm³/s) was injected into the mercury bath through an orifice of 0.2cm in diameter. The gas jet behavior was observed by using a high speed camera.
It was observed that, when jetting occurs, many tiny droplets are formed in the gas jet at the orifice exit. The present result for bubbling-jetting transition agrees well with the previous data obtained by three-dimensional bath. The injected gas does not form a continuous gas channel even in the sonic velocity region. The injected jet breaks up at some distance from the orifice exit, leaving a gas jet residual. The minimum length of the gas jet residual is fixed for each gas flow velocity. Thus, it has been found that the gas phase forms a small continuous jet extending from the orifice exit to the top of the jet residual.