Parallel simulation of high reynolds number vascular flows

The chapter provides an overview of the governing equations, time advancement scheme, and spectral element method. The chapter describes boundary condition treatment for simulating transition in bifurcation geometries. The chapter also presents parallel considerations and performance results, and provides results for transitional flow in an arteriovenous graft model. The simulation of turbulent vascular flows presents significant numerical challenges. Because such flows are weakly turbulent, they lack an inertial subrange that is amenable to subgrid-scale (SGS) modeling required for large-eddy or Reynolds-averaged Navier-Stokes simulations. The only reliable approach at present is to directly resolve all scales of motion. While the Reynolds number is not high, the physical dissipation is small. Weakly turbulent blood flow-such as the one that occurs in post-stenotic regions or subsequent to graft implantation-exhibits a much broader range of scales than does its laminar counterpart, and thus requires an order of magnitude increase in spatial and temporal resolution, making fast iterative solvers and parallel computing necessities.