Lagrangian properties of the blood flow through human and murine aortic arches: towards improved customised therapies and diagnostic techniques

The mass transport properties of the blood flow in the aortic arch are investigated by means of direct numerical simulations. The aortic arches in human and murine cases are assumed to be similar (with similarity factor equal to 20) and characterised by constant diameter, while the axis lays on a plane. The simulations were carried out using OpenFOAM (v.10). The flow regime appears remarkably different in the two cases because flow separation and vortical structures appear during the systolic phases in the human case, which are absent at the mouse scale. Consequently, peaks of the wall-shear-stress occur at different phases and, in the murine case, are characterised by a magnitude nearly 4 times larger than in the human case. The trajectories of fluid particles are computed in order to evaluate the dispersion efficiency exploited by biomedical applications (e.g. drug delivery or solid micro carriers). Despite the different flow regimes, in both system particles uniformly released at the inlet preserve a homogeneous distribution as they flow in the aortic arch. In particular, during the early decelerating phases of systole, the fluid trajectories are found frequently to approach the zones of the wall where the shear-stress is large.