Fluid-structure interaction modeling of blood flow in the pulmonary arteries using the unified continuum and variational multiscale formulation

•The variational multiscale formulation is constructed based on a unified continuum model for fluid-structure interaction simulation of blood flow in a pulmonary arterial tree.•The arterial wall is modeled by a fully incompressible hyperelastic material model.•The patient-specific geometry is constructed from medical images with variable wall thickness.•The outflow boundary conditions are modeled by the lumped parameter network to achieve physiological flow and pressure.•The simulation results are compared against those of a rigid wall simulation. In this work, we present a computational fluid-structure interaction (FSI) study for a healthy patient-specific pulmonary arterial tree using the unified continuum and variational multiscale (VMS) formulation we previously developed. The unified framework is particularly well-suited for FSI, as the fluid and solid sub-problems are addressed in essentially the same manner and can thus be uniformly integrated in time with the generalized-α method. In addition, the VMS formulation provides a mechanism for large-eddy simulation in the fluid sub-problem and pressure stabilization in the solid sub-problem. The FSI problem is solved in a quasi-direct approach, in which the pressure and velocity in the unified continuum body are first solved, and the solid displacement is then obtained via a segregated algorithm and prescribed as a boundary condition for the mesh motion. Results of the pulmonary arterial FSI simulation are presented and compared against those of a rigid wall simulation.