The Generation of Vortex Rings

The formation of a vortex ring of colored liquid ejected vertically upwards from a mouthpiece into still water is photographed.Comparing a number of these photographs, an interpretation is given for the mechanism of the generation of a vortex ring, which may be summarized as follows :1) The ejected liquid is first piled up over the mouthpiece, then immediately begins to curl axisymmetrically owing to the friction of the surrounding water.2) The liquid column connecting the rotating liquid mass with the mouthpiece is stretched and finally broken as the mass goes up in the water.3) The upper half of the broken column is hauled up gradually into the whirling liquid, and 4) In the end a vortex ring is completed when a hole is made at the center.These processes are illustrated schematically by a, b, c, and d of Figure 3 in the text.