Effect of upper layer immiscible liquids on the water entry phenomena

Abstract The influence of a thin upper layer liquid on the cavity dynamic and the phenomena of solid bodies entering into a two-layer system of immiscible liquids are experimentally studied. The new phenomenon is seldom documented in the literature. The thin upper layer silicone oil can affect the cavity profile, the seal time (surface and deep), and the pinch-off position of the cavity. The cavity dynamics and water entry phenomenon of the bullet with different diameters and head cone angles under varying upper layer liquid are studied. The critical Froude number (from deep seal to surface seal) is affected by the cone angle and the upper layer liquid. The pinch-off time of the deep seal cavity is affected by the diameter of the bullet but has nothing to do with the upper layer liquid and cone angles.