Crater Dynamics of a Water Droplet Impacts on the Oil Film Floating above the Water Bath
In order to explore the crater characteristics of droplet impacting on the oil film floating above the deep pool,experimental study and theoretical analysis were used to investigate cavity dynamics,,and a multi-interfaces model was proposed.The results show that that the immiscible properties of the droplet-oil film-liquid pool leads to a more complex cavity evolution process.It is concluded that for a smaller Froude number Fr,the daughter droplets are mainly generated by the Rayleigh-Plateau instability of the downward jet.For large Fr,the Rayleigh-Plateau instability due to the shrinkage of deformed droplets is the main reason of daughter droplets formation.Due to the effect of shear stress on the immiscible interfaces,the initial expansion rate of the cavity decreases with the increase in the number of deformed interfaces.For the thin liquid film,since the interfacial energy of the oil film-deep pool interface deformation is incorporated,the dimensionless depth of the cavity d'and Fr does not satisfy the classical relationship with d'～Fr1/4.In contrast,for the thick liquid film,its impact process can be regarded as a droplet impacting the oil deep pool,and the experimental observation satisfies the classical relationship.Moreover,the relationship between the effective cavity depth de' and Fr obtained by using the multi-interfaces model roughly meets the scaling law de'～Fr1/4.
万方数据
维普
