A Fully Parallelizable Loosely Coupled Scheme For Fluid-Poroelastic Structure Interaction Problems*

We investigate the fluid-poroelastic structure interaction problem in a moving domain, governed by a Navier–Stokes–Biot (NSBiot) system. First, we propose a fully parallelizable, loosely coupled scheme to solve the coupled system. At each time step, the solution from the previous time step is used to approximate the coupling conditions at the interface, allowing the original coupled problem to be fully decoupled into seperate fluid and structure subproblems, which are solved in parallel. Since our approach utilizes a loosely coupled scheme, no subiterations are required at each time step. Next, we conduct the energy estimates of this splitting method for the linearized problem (Stokes–Biot system), which demonstrates that the scheme is unconditionally stable without any restriction of the time step size from the physical parameters. Furthermore, we illustrate the first-order accuracy in time through two benchmark problems. Finally, to demonstrate that the proposed method maintains its excellent stability properties also for the nonlinear NSBiot system, we present numerical results for both two-dimensional and three-dimensional NSBiot problems related to real-world physical applications.