Abstract Three-phase fluid-structure interaction (FSI) problems couple the motion of solid structures and two different fluids, often exhibiting complex dynamics and posing challenges for computational investigation. The main objective of this paper is to present a new computational framework for the modeling, simulation, and application of such problems. To that end, we propose an integrated numerical algorithm that utilizes the volume of fluid method for the two-fluid flow and the immersed boundary method for the fluid-solid interaction, with a special emphasis on three-phase FSI computation in micro-scale settings. To demonstrate our methodology, we conduct a pilot FSI study on cellulose microfibrils in plant cell walls by simulating the interaction between microfibrils and two fluids, pectin and water. We investigate the evolution of the flow fields, the speed and spatial organization of the microfibrils, and the impact of different initial settings on microfibril dynamics. We find that the microfibril-pectin-water interaction leads to transversely oriented microfibrils with respect to the elongation axis of the plant cell. The simulation results indicate that our methodology may provide a novel approach to investigate the complex behavior of microfibrils and gain insights into the intrinsic dynamical properties of such microstructures.
Murshed et al. (Thu,) studied this question.