Abstract

This dissertation presents the first attempt to verify the capability of smoothed particle hydrodynamics (SPH), a meshfree particle method, to simulate pulsatile flow in the cardiovascular system. Smoothed particle hydrodynamics has been extensively used to simulate astrophysical phenomena, free surface flows and transient start-up of the internal flows under constant driving forces at low Reynolds numbers. However, most of the fluid flow phenomena are naturally unsteady with moderate Reynolds numbers. In this thesis, first, a series of benchmark cases are conducted to address internal oscillating flows at moderate Reynolds numbers. The performance of the two most commonly used formulations to model the diffusing viscous term and the XSPH variant, proposed to modify the movement of the particles, is investigated. The relation between particle resolution and sound speed to control compressibility effects in SPH simulations and the spatial convergence rate of the SPH discretization are examined. Furthermore, a modified formulation for wall shear stress calculations is suggested and an approach to implement inflow and outflow boundary conditions in SPH is introduced. It is also shown how SPH simulations with different particle resolutions exhibit behaviors equivalent to a finite volume scheme of different accuracy orders for moderate Reynolds numbers. The application of SPH to cardiovascular fluid dynamics is extended by simulating pulsatile flow inside a model of the heart’s left ventricle and through normal and dysfunctional prosthetic mechanical heart valves. The SPH simulations result in the realistic calculation of the shear stress loading on the blood components and illustrate the important role played by non-physiological flow patterns to shear-induced hemodynamic events.