No abstract

Drop impact onto a thin liquid film of another liquid is observed and characterized using a high-speed video system. A new mode of splash – a complete, simultaneous corona detachment – has been observed, which is the result of the lamella breakup near the wall film. The abrupt outward and upward displacement of the lamella leads to an extreme stretching of the corona wall, resulting in its rapid thinning and a rupture. This rupture triggers propagating Taylor–Culick rims, which rapidly spread, meet and, thus, undercut simultaneously the entire corona, resulting in its detachment. Special experiments with the spreading corona impingement onto a fixed needle, supplement the physical evidence of the above-mentioned mechanism. A self-consistent theory of the observed phenomena is proposed and compared with experiments, exhibiting good agreement.

While the phase-field methodology is widely adopted for simulating two-phase flows, the simulation of an arbitrary number (N ≥ 2) of fluid phases at physical fidelity is non-trivial and requires special attention concerning mathematical modelling, numerical discretization, and solution algorithm. We present our most recent work with a focus on validation for multiple immiscible, incompressible, and isothermal phases, enhancing further our library for diffuse interface phase-field interface capturing methods in OpenFOAM (FOAMextend 4.0/4.1). The phase-field method is an energetic variational formulation based on the work of Cahn and Hilliard where the interface is composed of a physical diffuse layer resembling realistic interfaces. The evolution of the phases is then governed by the minimization of the free energy of the system.The accuracy of the method is demonstrated for a number of test problems, including a floating liquid lens, bubble rise in two stratified layers, and drop impact onto thin liquid film.

No abstract

Drop impact onto a thin liquid film of another liquid is observed and characterized using a high-speed video system. A new mode of splash -a complete, simultaneous corona detachment -has been observed, which is the result of the lamella breakup near the wall film. The abrupt outward and upward displacement of the lamella leads to an extreme stretching of the corona wall, resulting in rapid thinning and a rupture of the corona wall. This rupture triggers propagating Taylor-Culick rims, which rapidly spread, meet and thus undercut simultaneously the entire corona, resulting in its detachment. Special experiments with the spreading corona impingement onto a fixed needle, supplement the physical evidence of the above-mentioned mechanism. A self-consistent theory of the observed phenomena is proposed and compared with experiments, exhibiting good agreement.