Interaction between two spheroidal drops in Couette flow: impact of initial offset and deformability

The collision of two spheroidal drops in a shear flow is simulated in this paper using the finite difference/front tracking method. The influences of deformability, initial offset, and the size of drops on their collision dynamics are assessed. It is demonstrated that the non-dimensional relative trajectory of a pair of drops, ∆z/R, is enhanced gradually as they approach and then, gains a maximum value and finally, reaches a new constant value after separation. An enhancement in the capillary number results in an increase in the deformation of the drops. The deformation and the time required for the collision of two drops are reduced as their initial offset is enhanced. It is revealed that as the ratio of major diameter to minor diameter of spheroidal drops is intensified, their deformation is enhanced.