THE INFLUENCE OF LIQUID FILM THICKNESS ON CROWN DEVELOPMENT: CROWN SHEET ANGLE
Droplet impact upon a liquid film is a phenomenon widely observed in nature but also extensively reported in the literature for a variety of different applications . Fuel injection in internal combustion engines is one of the many applications of studying this type of impact. Among all possible outcomes of a single droplet impinging on a liquid wall, crown splash is one of the most studied phenomena. Yet, it is not completely understood and several researchers seek to understand all physical mechanisms involved and their features. In previous works,  focused their work on a specific phenomenon that follows crown splash. Bubble encapsulation
happens when the crown liquid sheet bends inwards and eventually the jets on top of the crown merge creating an empty bubble above the horizontal liquid film as shown in Fig. 1. The formation mechanism of this phenomenon is not completely understood, but the crown sheet angle α certainly plays a significant role in its formation. In this way, crown development was investigated for a range of different impact parameters to understand how the crown sheet angle evolves after impact and until the crown collapse.