Impact Dynamics of a Viscoelastic Ferrofluid Droplet Under the Influence of Magnetic Field

In the present investigation, we explore the morphological evolution of a ferrofluid drop impacting on a solid substrate in the presence of a vertical magnetic field. The morphological evolution of the droplet is quantified by the change in its height, diameter, and contact line velocity. Two types of liquid drop are used in the present investigation viz. a water-based ferrofluid drop and a glycerol-based ferrofluid drop. The glycerol-based ferrofluid droplet acts as a viscoelastic drop. A comparative analysis of the impact dynamics is carried out between two different liquid drops in the presence/absence of a magnetic field. It is shown that the effect of fluid elasticity brings about a controllability on the impact dynamics in the presence of a magnetic field. The experimental investigations revealed that the viscoelastic ferrofluid drop in the absence of a magnetic field encounters a negligible recoiling effect. However, in the presence of a vertical magnetic field, the drop experiences significant recoiling of the contact line. Also, it is shown that the maximum deformation encountered by the drops is directly related to the strength of the applied magnetic field.