Numerical simulation of jet break-up in the second-wind induced regime using the local front reconstruction method

Abstract

In the second wind-induced regime, the jet deformations are influenced by aerodynamic instabilities acting on the jet surface. In addition, velocity relaxation in the liquid is an important mechanism with a strong influence on the violent break-up of laminar jets (i.e., the bursting). The exact interplay between the aerodynamic forces and the velocity profile relaxation is insufficiently described in the literature. Thus, we investigate numerically cylindrical liquid jets with fully developed and uniform velocity inlet profiles for different liquid and gas properties to elucidate the physical mechanisms governing the bursting of the jet. For this study, the gas-liquid interface is tracked using a front tracking technique: the Local Front Reconstruction Method (LFRM). In contrast with traditional front tracking techniques, LFRM allows for complex topological changes (merging and break-up) while keeping a sharp representation of the interface. The comparison of the obtained results with literature suggests that LFRM is a suitable technique for capturing the complex morphological deformations of a bursting jet. Additionally, we analyzed the influence of air and liquid properties on the jet deformations, which evidenced that velocity profile relaxation plays an important role in the complex process of break-up of the jet, that in combination with the destabilizing effect of the aerodynamic forces lead to the bursting of the jet.