We conducted an experiment on water exit with an air jet, using a cylinder with an ogival nose moving at a preset velocity. The air jet opens the water and forms a cavity that allows the cylinder to move within the air jet-induced cavity. We investigated the evolutionary patterns, morphological, and geometric characteristics of the cavity formed by the air jet, varying exit velocities, nozzle diameters, and air injection rates. For underwater cavity formation, three distinct cavity flow patterns were observed across all of our experiments: Bubbly flow (BF), unstable cavity (UC), and jet cavity (JC). Moreover, UC can be further divided into unstable partial cavity (UPC) and unstable continuous cavity (UCC), depending on the relative geometry between the cavity and the cylinder. During free surface penetration in the JC regime, two distinct cavity flow patterns arising from the interaction between the cavities and the cylinder have been identified: attached ventilated cavity (AVC) and collapsed ventilated cavity (CVC), corresponding to different momentum ratio ranges. The AVC is proposed as a potential solution for achieving a stable water exit without cavity collapse. Furthermore, the geometry of the ventilated cavity in the JC regime follows a power-law relationship with the momentum ratio.

Close

PrevNext

View figure in article

• Cavitation
• Drag reduction
• Interfacial flows