Unsteady flow of thin liquid film on a disk under nonuniform rotation

Development of thin liquid film under nonuniform rotation has been studied numerically by using finite difference technique under the assumption of planar interface. For impulsive rotation of the disk an anomalous behavior of the rate of film thinning with the variation of the Reynolds number is observed in a different time zone. It is also shown that the azimuthal velocity field develops into the entire depth faster with the smaller impulsive rotation. A physical explanation for the above observation is provided. Further it is found that faster rate of thinning can be obtained if the spinner starts impulsively and then increases its spinning rate continuously.