Liquid film formation on a rotating disk (numerical analysis at the initial stage)

Unsteady liquid film flow ona rotating disk which is related to a spin coating technique to form a uniform thin film on a plate is calculated numerically. A newly developed calculation method which takes the surface tension on the liquid surface into account is applied. The numerical results reveal the following: the hemispherical liquid on the disk, which starts to rotate impulsively from rest, spreads by gravitational forces at the first stage. The development of the distribution of radial and azimuthal velocities is affected complicatedly by the Coriolis forces viscous forces and centrifugal forces. The liquid spreads mainly by centrifugal forces and forms a uniform thin film on the disk at the last stage. The surface tension only shows a little influence on the spreading process at the first stage.