I am a geologist Studying crystal settling through Newtonian fluid-Fluids.

I am a 4th Year geology doing analogue experiments of 'Crystals' Falling through Newtonian Fluid-fluid interface (Golden Syrup and Sunflower Oil). The Crystals are of Different Aspect rations and pass through a fluid-fluid interface. I need to describe my system mathematically, using dimensionless numbers, bond Number, Reynolds number ect. This is so I can scale my project to wider work in understanding magma chambers. What else do I need to consider when describing a settling particle (especially one using cylinders instead of spheres).

1) What do I need to consider when Describing Mathematically a settling particle through a fluid-fluid interface, What other dimensionless numbers can I use?

2) Is there any special considerations when describing a cylinder rather than a sphere.

3)What is the special significance of using Newtonian fluids (apart from being analogue to natural systems) how would it affect my project by using Newtonian fluids?

4) my project is an interface dominated fluid and by changing the particle aspect ratio I also change the weight (increasing aspect ratio increases the weight) therefore they pass though easier being dominated by settling forces. How can I describe this mathematically, what laws do I need to understand to show why this happens.

Any help would be greatly appreciated?