Spray breakup and droplets impacting with model transition

The droplets' impact on a liquid surface is widespread in daily life and industrial applications. A high-fidelity and efficient numerical method is necessary for the droplets' impact on a liquid surface during the spray process. This study introduces a novel integrated VOF-to-DPM-to-VOF (Volume of Fluid-to-Discrete Particle Model-to-Volume of Fluid, VtDtV) method by combining spray breakup and droplet impact modeling through the VTD (VOF-to-DPM) and DTV (DPM-to-VOF) approaches, enabling accurate model transition within the computational domain and achieving precise simulation of droplet impacts on a free liquid surface in large-scale fields. Different simulation models are employed in different regions/stages to balance computational efficiency and accuracy. The VTD method is used to capture the liquid film breakup process, while the DTV method is used to analyze the details of droplet impact, and DPM serves as a bridge for transitions over large spaces. Finally, in contrast to most previous works that primarily focus on energy transfer during the vertical impact, this study completes the analysis of droplets impacting the liquid surface during the spray process, discussing the morphology and energy involved in both single and multiple droplets oblique impacting on the free liquid surface and predicting the size of the cavity. The results show that the prediction formula for the maximum cavity depth of the single droplet oblique impact model has an error of 14.71%, and the maximum error for the impact of multiple consecutive droplets is 4.61%, verifying the accuracy of both the simulation method and the analysis model.