回転円板上の液滴の挙動に関する研究(熱工学,内燃機関,動力など)  [in Japanese] On the Sliding and Profile of a Liquid Droplet on a Rotating Disk(Thermal Engineering)  [in Japanese]

The theoretical and experimental study was conducted to investigate the critical condition at which a liquid droplet starts to move on a rotating disk. Based on the force balance between the surface tension and the centrifugal force, the critical rotation speed was theoretically calculated in the similar manner to the preceding report. The critical rotation speed was experimentally measured for each combination between three kinds of test plates and test liquids. The movements of droplets were judged from the careful observation of infinitesimal motion of the three-phase contact line. The calculated rotation speeds agreed well with measured ones for any contact angle when the droplets were set on the plate. The three-dimensional surface profiles of droplets were calculated from the approximate Laplace equation in which the contact line was assumed as the combination of two ellipses with different ratio of measure to minor axis. The measured profiles on the rotating disk were approximated well by the method proposed in this study.