Fluid-structure simulations and benchmarking of artery aneurysms under pulsatile blood flow

In this paper Fluid-structure interaction (FSI) simulations of artery aneurysms are carried out where both the fluid flow and the hyperelastic material are incompressible. We focus on time-dependent formulations adopting a monolithic approach, where the deformation of the fluid domain is taken into account according to an Arbitrary Lagrangian Eulerian (ALE) scheme. The exact Jacobian matrix is implemented by using automatic differentiation tools. The system is modeled using a specific equation shuffling that assures an optimal pivoting. We propose to solve the resulting linearized system at each nonlinear outer iteration with a GMRES solver preconditioned by a geometric multigrid algorithm with an Additive Schwarz Method (ASM) smoother. In order to test our numerical method on possible hemodynamics applications, we describe several benchmark settings. The configurations consist of realistic artery aneurysms where hybrid meshes are employed. Both two and three-dimensional benchmarks are considered. We show numerical results for the described aneurysm geometries focusing on pulsatile inflow conditions. Parallel implementation is addressed and a case of endovascular stent implantation on a cerebral aneurysm is presented.