抄録
Flow around a sphere desending under the gravity in still and viscous fluid were visualized by means of tracer-particle method. And the locations of the sphere were analyzed using two cameras mounted perpendiculary. It is shown experimentally that the sphere desends curvedly in a plane containing the perpendicular axis and the separaton of a vortex-ring are ovserved. And some of the fundamental features were elucidated by these experiments.
