65 巻 (1999) 637 号 p. 3022-3028
Unsteady non-uniform liquid film flow on a rotating disk. which starts to rotate impulsively from rest, is analyzed by asyptotic methods. A short-time-scale expansion for the transient film profile near the rotating axis is derived as a function of space and time. The effects of gravitational force and surface tension as well as centrifugal force are identified for a case in which the initial film thickness is even function of radial component and the non-uniformity in film thickness is much smaller than the film thickness itself. In this time scale, the centrifugal force has little effect on the spreading process at the very beginning of the stage due to the effect of the local inertia, while it becomes dominant as the angular velocity of the film develops. The gravitational force has smaller influence on film than the centrifugal force, but the rate of its effect takes the same order of magnitude through out this time scale. Although the surface tension has even smaller influence on the process, it prevents the liquid from spreading.