Influence of an upper layer liquid on the phenomena and cavity formation associated with the entry of solid spheres into a stratified two-layer system of immiscible liquids

Abstract

New phenomena not previously documented in the available literature have been experimentally observed subsequent to the entry of falling steel spheres into a stratified system of a shallow layer of sunflower oil above a deep pool of water. Further experiments on similar sphere entries into sunflower oil demonstrated that these phenomena arose mainly as a result of the interaction between the surface of the spheres and the sunflower oil. It should be noted that the sunflower oil layer in the aforementioned two-layer system was relatively very thin compared to the dimensions of the spheres. Therefore, the experiments showed the substantial influence both the upper layer liquid and the surface conditions of the solid body could potentially have on the phenomena and cavity dynamics that arise as a result of solid entries into stratified two-layer systems of immiscible liquids.

Water entry of spheres into a rotating liquid

“…Later, it contracts due to the hydrostatic pressure, leading to a pinch-off at t = 77.0 ms. This type of pinch-off was referred to as a 'deep seal' in prior work, as it occurs at a significant depth below the water surface when compared to other cavity-sealing phenomena (Lohse et al 2004;Aristoff & Bush 2009;Tan & Thomas 2018). The corresponding cavity is referred to as a deep seal cavity.…”

Impact of a Linear Array of Hydrophilic and Superhydrophobic Spheres on a Deep Water Pool

“…Experimental studies on the water entry of solid bodies have focused mainly on the effects of: (i) the size and shape of the solid body (see Figure 5 in [3]), (ii) the surface wetting and roughness characteristics of the solid body (see Figure 2 in [3]), (iii) the impact velocity and rotation of the solid body at entry (see Figure 8 in [3]), (iv) the density of the solid body material compared to that of the liquid pool (see Figure 6 in [3]), and (v) the presence of oil film on the free surface of water [4] on the dynamics of the cavity below the free surface of a liquid pool and the dynamics of the splash above the free surface of a liquid pool.…”