The effect of entrance flow development on vortex formation and wall shear stress in a curved artery model

TL;DR

This study numerically examines how different entrance flow conditions influence vortex formation and wall shear stress in a curved artery model, revealing significant effects on secondary flow patterns and potential implications for cardiovascular disease.

Contribution

It demonstrates the impact of entrance flow development on vortex dynamics and wall shear stress distribution in a simplified curved artery model using high-order spectral element simulations.

Findings

Entrance conditions significantly affect vortex formation.

Deceleration phase shows coexistence of Dean and Lyne vortices.

Wall shear stress variations may relate to cardiovascular risk.

Abstract

We numerically investigate the effect of entrance condition on the spatial and temporal evolution of multiple three-dimensional vortex pairs and wall shear stress distribution in a curved artery model. We perform this study using a Newtonian blood-analog fluid subjected to a pulsatile flow with two inflow conditions. The first flow condition is fully developed while the second condition is undeveloped (i.e. uniform). We discuss the connection along the axial direction between regions of organized vorticity observed at various cross-sections of the model and compare results between the different entrance conditions. We model a human artery with a simple, rigid $180^\circ$ curved pipe with circular cross-section and constant curvature, neglecting effects of taper, torsion and elasticity. Numerical results are computed from a discontinuous high-order spectral element flow solver. The flow rate used in this study is physiological. We observe differences in secondary flow patterns, especially during the deceleration phase of the physiological waveform where multiple vortical structures of both Dean-type and Lyne-type coexist. We highlight the effect of the entrance condition on the formation of these structures and subsequent appearance of abnormal inner wall shear stresses - a potentially significant correlation since cardiovascular disease is known to progress along the inner wall of curved arteries under varying degrees of flow development.