sphere in a free surface (thin film)flow
 

hi, i am trying to model motion of a sphere in a flowing thin film. the film is generated on an inclined smooth plane. particles (spherical in shape) are introduced into the flow. particle sizes varies from smaller than film to larger than film. i need to model the problem to predict the velocity of the particle. the particle is in touch with the plane at the bottom (solid) and may interact with the free surface depending on the size. for instance, when it is comparable to the film thickness (but smaller than the film thickness), it's movement may distort the free surface. when it is larger than the film thickness, it will protrude out and the film will rise around the particle (surface tension - capillarity).

i am trying to model it using finite difference method (the only method i know in CFD).

and i am having problems with everything: 1. grid generation 2. free surface boundary condition 3. accounting for the motion of the particle.

any suggestions will be greatly appreciated!!!