Instability in three-dimensional, unsteady, stenotic flows

The paper presents a computational investigation of instabilities in pulsatile flow through a three-dimensional stenosis. The computations have been conducted using a third-order high-resolution scheme and a non-linear multigrid algorithm. The simulations reveal the existence of unstable flow throughout the pulsatile cycle. The instability is manifested by asymmetric flow patterns––though the stenosis is axisymmetric––large flow variations in the cross-sectional planes, and swirling motion in the poststenotic region. The instability leads to a strongly disturbed flow several radii downstream of the stenosis, as well as spatio-temporal fluctuations of the circumferential shear stress and vorticity.