  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-$\alpha$ 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.
