Cavitation upon low-speed solid-liquid impact

Area of Science:

• Fluid dynamics
• Physics of impacts
• Material science

Background:

• Classical studies predict infinite pressure during flat solid-liquid impacts.
• Real-world observations and previous research indicate high pressures at impact sites.

Purpose of the Study:

• Investigate the possibility of cavitation during low-speed solid-liquid impacts.
• Challenge the assumption of universally high pressures in such scenarios.
• Develop a predictive model for cavitation onset.

Main Methods:

• Experimental setup involving a flat-bottomed cylinder impacting a liquid pool.
• Analysis of pressure dynamics and wave propagation during impact.
• Development of a novel cavitation number based on experimental data.

Main Results:

• Observed cavitation at impact velocities as low as ~3 m/s.
• Demonstrated that impacting cylinders can reduce local pressure, inducing cavitation.
• Identified negative pressure regions formed by reflected pressure waves.

Conclusions:

• Low-speed solid-liquid impacts can lead to cavitation, contrary to classical predictions.
• The proposed cavitation number effectively predicts cavitation onset in these scenarios.
• Findings have implications for understanding impacts in diverse applications like boat slamming and spacecraft landings.