Experimental investigation on the development features of a gas jet on the surface of a vertical moving body with a constant volume chamber

Based on the motivation of trajectory stabilization using a stable air layer generated by multi-point injection, the dynamic behaviors of a bubble exhausted from a single-hole have been studied experimentally. The pressure inside the air chamber is recorded by the pressure sensor, and the bubble dynamic behaviors are captured by high-speed cameras. First, the repeatability of the experiment is validated and an indirect method to measure the bubble volume is introduced. Subsequently, according to experimental results, a flow feature map is constructed to depict the bubble morphologies under different conditions, where two stable modes and three unstable transition modes can be observed. Moreover, the formation mechanism of different modes has been studied. Finally, based on the investigation of bubble morphologies, pressure evolutions, and bubble scales under different initial pressure inside the air chamber and motion states of the model, the effects of the initial pressure inside the air chamber and motion state of the model are analyzed. The generation of the gas jet can be delayed by the washing effect of the incoming water flow while the large pressure difference can promote the generation of the gas jet. The bubble dynamic behaviors are the result of mutual interaction between the two effects.