液滴和液面碰撞

COLLISION OF A WATER DROP ON WATER

A series of experiments were performed to study the impact of a water drop-with various vilocities, ranging from 0 to 600 cm/s, on to a water surface. There are three-kinds of phenomena. Two of which, we named them "penetration" and "cleavage", were observed for low impact velocity (up to 100 cm/s). Their common characteristics are that no-obvious disturbances on the surface were observed during the colKding process, namely no splashing jets nor obvious crater were observed. By penetration we mean that a drop that has fallen into water becomes a ring, which penetrates the water smoothly with a velocity of several centimeters per second. During the penetrating process no obvious change of its configuration was observed. The falling height corresponding to penetration is proportional to the volume of the original drop. Some periodicity of these falling heights (corresponding to penetration) was revealed. The phenomenon named by "cleavage" occurs when the impact velocity is other than that corresponding to penetration, then the falling drop cleaves into an "inverted cauliflower" to appear below the surface of the water. It almost not decends. By diffusing and slowly expanding it vanished in the vessel water several minutes after. These two phenomena, as known by us, have not been reported before. As the impact velocity approaches or exceeds 100 cm/s, the third phenomenon, "splash", appears. The diameter and depth of the crater occuring in the case of splash, together with the tieme for the crater to reach its maximum Size, and the time for the rebounding column to begin to rise are given as functions of the falling height of the drop.