A Non-staggered Projection Algorithm for Two-Phase Fluid-Structure Interaction Simulation Using the Phase-Field/Immersed-Boundary Method

TL;DR

This paper introduces a non-staggered projection algorithm for multiphase fluid-structure interaction that effectively suppresses pressure oscillations and accurately captures interface dynamics on a Cartesian grid.

Contribution

It presents a novel pressure-oscillation-free projection method combined with phase-field and immersed boundary techniques for large-density-ratio multiphase FSI simulations.

Findings

Successfully suppresses unphysical pressure oscillations.

Accurately captures multiphase interface evolution.

Validated with lid cavity, droplet deformation, and bubble obstacle cases.

Abstract

We present a Pressure-Oscillation-Free projection algorithm for large-density-ratio multiphase fluid-structure interaction simulations, implemented on a non-staggered Cartesian grid. The incompressible Navier-Stokes is decoupled with an improved five-step incremental pressure correction algorithm. Fluid-fluid interface is captured using the Cahn-Hilliard equation, and the surface tension model is coupled with a momentum-weighted interpolation scheme to suppress unphysical pressure oscillations, ensuring accurate evolution of multiphase interfaces. Interaction at the fluid-structure interface is obtained by implicitly solving for the feedback acceleration in the Eulerian-Lagrangian system. For validation of the present method, the comparison studies for Pressure-Oscillation-Free effect are systematically conducted using lid driving cavity and droplet deformation cases. Moreover, several challenging multiphase simulations are implemented and discussed. As a demonstrating example of fluid-structure interaction, a rising bubble bypassing an obstacle is tested.