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Aerobreakup of liquid drops are important to many droplet applications, such as fuel injection. When a liquid drop is subjected to a gas stream of high velocity, the drop can deform and break into small droplets. The drop aerobreakup is controlled by multiple dimensionless parameters. The Weber number (We) has been commonly used to characterize the different breakup regimes. While the effects of Weber and Ohnesorge numbers on the aerobreakup of a drop in unbounded domain have been extensively studied, the effect of the Reynolds number (Re) based on gas properties are less understood and will be investigated by 2D axis-symmetric and 3D detailed numerical simulations in the present paper. Attention will be focused on the moderate We regime, where the drop mostly breaks in the bag mode. In many previous studies for millimeter drops, Re is too large to be relevant. However, for applications where drops are small and the relative velocity is high, Re can be quite small when the drop breaks. Parametric simulations of Re and We are performed to systematically investigate the effect of Re on the drop aerobreakup dynamics. The simulations are performed using the Basilisk solver, where the mass-momentum consistent VOF method is used to capture the interfacial dynamics on an adaptive mesh. The reduced Re is found to induce significant changes in the drop acceleration, deformation, bag morphology, and the bag breakup dynamics, which in turn lead to significant variation in the size and spatial distributions of the children droplets formed. 

In the present work, we model and simulate the injection and atomization of a gasoline surrogate jet by detailed numerical simulation. The surrogate fuel has a low volatility and thus no phase change occurs in the process. The nozzle geometry and operation conditions are similar to the Engine Combustion Network (ECN) “Spray G”. We focus the present study on the near field where inter-jet interaction is of secondary importance. Therefore, we have considered only one of the eight jets in the original Spray G injectors. The liquid is injected from the inlet into a chamber with stagnant gas. A tangential component of velocity is introduced at the inlet to mimic the complex internal flow in the original spray G injector, which leads to the jet deflection. A parametric study on the inlet tangential velocity is carried out to identify the proper value to be used. Simulations are performed with the multiphase flow solver, Basilisk, on an adaptive mesh. The gas-liquid interface is captured by the volume-of-fluid method. The numerical results are compared to the X-ray experimental data for the jet deflection angle and the temporal variation of penetration length. The vortex dynamics in the near field are also presented by the assistance of the vortex-identification criterion.