Abstract
Numerical study of high-speed submerged water jet accompanied with cavitation bubbles requires an adequate model that is capable of describing locally high pressures and the phase change due to strong collapse of bubbles. For this purpose, a system of averaged equations for two-phase bubbly flows is derived, where a surface average pressure of liquid is introduced in addition to volume average pressures taken for gas and liquid phases respectively. The surface average pressure is connected to the volume average pressures through the momentum jump condition. The mass and momentum transfers across the interface by the phase change are also taken into account, although a liquid temperature is assumed constant.
