Simulation of the co-axial ferrofluid droplets interaction under uniform magnetic field

Abstract

In this study, falling and the coalescence of a pair ferrofluid droplets subjected to uniform magnetic field are investigated numerically. For this approach, a 2-D hybrid approach combined of lattice-Boltzmann and finite volume method is used. The lattice Boltzmann equation with the magnetic force term is solved to update the flow field while the magnetic induction equation is solved using finite volume method to calculate the magnetic field. To validate current simulations, three test cases have been considered: Laplace, multiple rising bubbles and deformation of static drop under magnetic field are analyzed. The comparison of results between the present study and previous researches shows a good agreement. The effects of different parameters: magnetic Bond number, magnetic susceptibility, and magnetic field direction are comprehensively studied. The results show that the coalescence of droplets becomes fast with the increasing Bond number and susceptibility in y-direction magnetic field. Also, the coalescence and falling process of droplets takes more time in the horizontal magnetic field in comparison with the vertical magnetic field.