衝撃波管内のRAYLEIGH-TAYLOR不安定性の実験観察(<小特集>異相界面における諸現象の物理)

抄録

Rayleigh-Taylor instability in a shock tube has been invistigated experimentally. Such instability was produced by accelerating a liquid column down a vertical circular tube employing shock wave impact. In the experiments, water, decane and glycerin solution, were used respectively as the testing fluid to study the instability at the gas/liquid interface. A combination of decane and salt solution was used to study the instability at the liquid/liquid interface. The resulting instability of the gas/liquid interface and the liquid/liquid interface was recorded and later analyzed using high-speed video images. Cavity formation was observed in the middle of the gas/liquid interface soon after the shock wave impact ; bubbles and spikes then developed across the rest of the interfacial plane. Flow visualizations show that surface tension and viscosity greatly affects the instability development. Measurements show that the grouth coefficient of the cavity is about twice of that of the bubbles. The growth coefficient of the bubbles is nearly independent of the Atwood number, while the growth coefficient of spikes is sensitive to the Atwood number.