Characteristics of Bubble Bursting Dynamics in an Elastoviscoplastic Polymer Matrix: Effect of Fluid Elasticity and Plasticity.

Although bursting bubbles are widely encountered in nature and in engineering applications, the flow physics behind the bursting process and interfacial flow remain incomplete in complex fluids. In this work, we investigate the dynamics of bubble bursting in an elastoviscoplastic (EVP) polymer matrix by three-dimensional direct numerical simulations. The volume-of-fluid method coupled with a local adaptive mesh refinement technique is adopted to capture the gas-liquid interface, and the Saramito model is employed to describe the EVP rheology of realistic polymer fluids. The numerical model has been validated by comparison with experimental results, and the complex interplay between elasticity and yield stress effects on the transient interfacial phenomena of bursting bubbles has been studied. Using the dimensionless Weissenberg number Wi and plastocapillary number J to analyze the behavior of EVP polymer fluids, our results identify that there are five bubble bursting patterns under different Wi and J, and they provide broadly insights into the mechanisms of transition phenomena for different modes. It is indicated that yield stress has little effect on capillary wave intensity but influences jet development, with the jet height decreasing as plasticity increases. Interestingly, under the combined influence of elasticity and plasticity, a mode emerges where the entire cavity collapses, forming a satellite bubble at the liquid surface. Additionally, increased elasticity enhances energy focusing at the cavity bottom, while hindering jet droplet formation. A correlation of the reduced jet droplet radius with the Weissenberg number has been obtained. This study provides key insights into the industry applications involving complex polymer fluids as well as an understanding of the dynamics of interfacial bubble bursting.