Deformation of Freely Suspended Double Emulsion Droplets Via a 3D Spectral Boundary Element Method

Great interest in the behavior of double emulsion droplets arises due to its numerous applications in petroleum processing, pharmacy and food industry. Stone and Leal (JFM, 1990) studied the behavior of concentric double emulsion droplets with small deformation. However both concentric and eccentric double emulsion droplets with large deformation are more common in the aforementioned applications. In this work, we employ a 3D spectral boundary element method to investigate the behavior of double emulsion droplets with large deformation in linear flow. Boundary integral equations for freely suspended double emulsions are derived. The relationships between the deformation and the surface tensions, viscosities and droplet sizes are investigated. Both concentric and eccentric double emulsion droplets are included in our concern. The numerical results are validated by comparing to analytical predictions.