Fluid-structure interaction in a pulmonary arterial bifurcation

A numerical method is developed to solve the fluid-structure interaction in three-dimensional pulmonary arterial bifurcation with collapsible tubes. A self-developed FEM code is used to calculate the nonlinear deformation of the thin-walled structure and a commercial CFD solver, FLUENT, is used to resolve the fluid flow. The large deformation of the structure alters the flow field significantly while the fluid pressure affects the deformation of the structure strongly. In the bifurcation branches, the relatively short tube collapses into wave number N=3 mode. The strong collapse of the branch tube leads to a large contraction of the cross-sectional area and increases the resistance on the fluid flow. The recirculation occurs at both the up- and down-stream of the collapsed tube.