Investigation of Free-surface Flow Associated with Drop Impact: Numerical Simulations and Theoretical Modeling

This work is devoted to investigation of free-surface flow associated with drop impact. The main goal of the work is the computational and the theoretical study of the flow generated by drop collisions and drop impact onto different surfaces, with relevance for spray impingement. The considered flow configurations include drop impact onto a shallow liquid layer, binary drop collision, drop impact onto a dry wall, nonisothermal drop impact onto a heated wall with the accompanying simultaneous heat transfer within the wall, and drop impact onto a porous substrate. The potential of the new interface capturing methodology developed by OpenCFD Ltd and based on the volume-of-fluid (VOF) model within the framework of Computational Fluid Dynamics (CFD) is evaluated by contrasting the results of numerical simulations to the in-house experimental results and the existing experimental and numerical result databases. The novelty in the numerical approach is the introduction of an additional convective term into the equation for the indicator function, which acts as an artificial compressive contribution in the integrated equation and enables suppression of the numerical diffusion thereby providing a sharp definition of free surfaces. The flows studied are treated as being laminar and computed in the framework of the finite-volume numerical method. In general, the numerical model and the computational procedure demonstrate good predictive capabilities by reproducing correctly the studied flows mentioned above, both qualitatively and quantitatively. All important effects observed in the experiments are reproduced and particularly some distinctive features of the flow are properly captured. The numerical simulations of the different flow configurations pertinent to spray impact provide a detailed insight into the dynamics of the flow and enable analytical modeling using simplified theoretical approaches. In particular the computational results provide all the flow details which are inaccessible by present experimental techniques, they are used to prove the theoretical assumptions and yield the required database for defining new flow patterns and their analytical modeling.