Numerical Simulation of Forced Breakup of a Liquid Jet

Even nowadays, the physics of jet breakup is still not well understood and this is the reason why a lot of effort has been put recently into the investigation of this kind of flow. Within this framework, special attention has been focused on the use of excitation sources of defined amplitude and frequency in order to understand their effect on the (possible) jet disintegration process [SCO99, CGO+00]. The lack of analytical models for describing the strong non-linear behavior of this type of flow on the one hand, and the difficulty of accessing experimentally flow features like pressure and/or velocities on the other hand, have made it necessary to develop and use numerical methods for this purpose. In the recent past, numerical methods based on the Navier-Stokes equations with the possibility of handling free-surfaces have been developed and proved to fulfill the above requirements; they also have shown to be able to reproduce qualitatively well the jet-breakup behavior observed in the experiments [AMP00]. In the work presented here, after a brief description of the numerical method used, the results of simulations of the forced breakup of a round jet of ethanol into quiescent air will be presented. Three different types of excitation have been used and their effects on the jet breakup have been analyzed. Special attention has been paid to the capture of droplet generation.