The ejecting lamella of impacting compound droplets

Impacting dynamics of compound droplets consisting of oil and water–glycerol mixture transitions from spreading to splashing with an increasing volumetric oil-mixture ratio. The transition to splashing is directly related to the dynamics of the ejecting lamella upon impact. Here, we present a detailed study of the ejecting lamella at the early stage of the impact. We experimentally characterize the ejection velocity and time of the ejecting lamella for a wide range of impacting velocities, volumetric oil ratios, and viscosities of the mixture. We show that ejecting dynamics depends significantly on the volumetric oil-mixture ratio, while it is slightly affected by the viscosity of the mixture. We also propose and verify experimentally a predictive model for the ejection velocity and time of the lamella.Impacting dynamics of compound droplets consisting of oil and water–glycerol mixture transitions from spreading to splashing with an increasing volumetric oil-mixture ratio. The transition to splashing is directly related to the dynamics of the ejecting lamella upon impact. Here, we present a detailed study of the ejecting lamella at the early stage of the impact. We experimentally characterize the ejection velocity and time of the ejecting lamella for a wide range of impacting velocities, volumetric oil ratios, and viscosities of the mixture. We show that ejecting dynamics depends significantly on the volumetric oil-mixture ratio, while it is slightly affected by the viscosity of the mixture. We also propose and verify experimentally a predictive model for the ejection velocity and time of the lamella.