抄録
A theoretical and experimental study is conducted to discuss the spontaneous dropping of liquid in a vertical capillary pipe with a lid at the top end. The system energy was calculated when the pipe is inclined to the horizontal direction. The pendant liquid surface formed at the pipe end becomes unstable if the infinitesimal energy change is negative when the three-phase contact line shifts upward on the pipe inner wall. The critical inclination of the pipe is calculated theoretically and the results agree with those obtained experimentally for various kinds of test liquids.
