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Abstract
A single drop impact on a liquid film is numerically investigated using the coupled level set and volume of fluid (CLSVOF) method. Influences of gas properties including gas density and viscosity on the crown liquid sheet behavior and the drop-film coalescence process are mainly discussed. It is found that the decrease in the liquid–gas density ratio will result in incurve of the crown, especially when the density ratio is less than 100, due to the large gas velocity difference between the crown upper and lower positions. When the liquid–gas viscosity ratio is decreased to a value of less than 0.5, both splashing occurrence and crown expansion are suppressed, caused by the combination effect of the pressure difference and the gas velocity in the drop-film-contacting neck region. The density ratio has only minor influence on the drop coalescence process. However, when the viscosity ratio is decreased, the capillary wave on the drop surface gradually disappears. It is considered that the gas eddy reduction on the drop surface should be responsible for the capillary wave disappearance during drop coalescence.
Notes
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