Topological Remeshing and Locally Supported Smoothing for Bubble Coalescence in Two-Phase Flows
Congress: COBEM
ABSTRACT:
A dual strategy of remeshing and smoothing operations is introduced into the recent Arbitrary Lagrangian- Eulerian/Finite Element code developed for modeling of two-phase flows and heat transfer. At the forefront, the approach is introduced not only to discretize the continuum filled by the liquid and vapor phases but also to represent their common interface by computational elements. While in synchrony, a Level-Set (LS) methodology has now been introduced to better model the coalescing regions. Therefore, this work presents a two-dimensional idealized model concerning the numerical modeling of the coalescence between two circular bubbles immersed in stagnant liquid. While the ALE/FE approach can guarantee suitable remeshing to recover the structure of the mesh after the thin liquid film disruption, the LS strategy locally determines the coalescing region by application of a function of compact support. The effect of the collapse is assuaged and any sharpnesses owing to local topological changes occurring in the contact region tend to be less protruding by smoothing. Two-dimensional numerical results show that this incipient methodology is a promising technique in regard to coalescence studies and is able to be extended, a posteriori, to three-dimensional cases. Developed mainly to deal with bubble interactions, these strategies aim to be embodied, in the future, into a two-phase flow context, especially to simulate the coalescence taking place in transitional regions of passage from bubbly-to-slug and slug-to-annular patterns.