Spreading of a compound drop upon impact on a solid surface

The impact of liquid drops on solid substrates is extensively studied due to its wide range of industrial and natural applications. Recently, attention is paid to impact of ‘compound drops’ i.e., drops made of two immiscible liquids in core-shell configuration. To date the effect of the viscosity on the spreading of such drops is not investigated fully. The core and encapsulating shell liquid layers used in the impact experiments are Newtonian with a range of viscosities, and core to shell size ratios. We will present our findings regarding spreading behaviour and its morphology as a function of relative viscosity, and volume ratio of two liquids. A regime map based on non-dimensional impact parameters will be discussed from first principles. A comparison with simple drops impact events is also provided.