Abstract
Experimental and numerical study on liquid jet occurrence in converging tubes is conducted, in order to clarify the detailed mechanism of the jet occurrence and bubble breakup phenomena. It is found experimentally that the liquid jet is observed in the converging tubes without divergent section, which indicates the divergent part has no contribution to the jet occurrence. It is also shown that the ratio between bubble diameter and tube diameter is more important for the jet velocity than the bubble diameter. Numerical results, which are confirmed to agree well with experimental results, show that the jet is caused by the steep gradient of a static pressure behind the bubble. The steep pressure gradient is locally and impulsively generated by the concentration of pressure difference and the convergence of flow behind the bubble.
