Elasto-capillary fluid-structure interaction with compound droplets

Computational modeling of elasto-capillarity, i.e., a fluid-structure interaction phenomenon where the solid deformation is driven by capillary forces at fluid-fluid interfaces has recently emerged as an important problem in computational mechanics. However, the high-fidelity simulation of elasto-capillary problems involving three immiscible fluids has remained unexplored. Here, we present a mathematical model and an algorithm to simulate elasto-capillary problems involving compound droplets. Such problems are of pivotal importance in pharmaceutical, biological and food industrial applications. We adopt a phase-field model described by the ternary Navier-Stokes-Cahn-Hilliard equations for the three immiscible fluids and a neo-Hookean model for the solid. We define a fluid-solid surface energy function, which determines the fluid-solid wettability and the tractions transmitted to the solid at the fluid-solid interface. We adopt a boundary-fitted approach for our fluid-structure interaction formulation and Isogeometric Analysis for the spatial discretization. To demonstrate the effectiveness of our computational model and algorithm, we perform elasto-capillary simulations involving various types of compound droplets.(c) 2022 Elsevier B.V. All rights reserved.