In this paper, electrohydrodynamics (EHD) deformation of a droplet in a highly confined domain is studied by using the incompressible smoothed particle hydrodynamics method. Simulations are performed for six different systems of a droplet and ambient fluid corresponding to different electrical properties. The effects of confinement ratios, from 0 to 0.95, on the droplet deformation are discussed thoroughly. It is shown that the deformation is highly dependent on the ratios of electrical permittivity, electrical conductivity, and confinement ratio. To demonstrate the droplet behavior, electric force components on the droplet interface are calculated and discussed in detail. It is shown that the interaction of these forces plays a major role in the droplet deformation. Furthermore, it is illustrated that the pressure force becomes significant at high confinement ratios and affects the droplet behavior in addition to the electric forces. Different values of unbounded deformation are selected for the EHD simulation. The effect of unbounded deformation on the droplet behavior is also discussed, and it is found that the unbounded deformation influence is important in some of the systems and confinement ratios.

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