Instability modes and transition of pulsatile stenotic flow: pulse-period dependence
نویسندگان
چکیده
منابع مشابه
Instability modes and transition of pulsatile stenotic flow: pulse-period dependence
The instability modes arising within simple non-reversing pulsatile flows in a circular tube with a smooth axisymmetric constriction are examined using global Floquet stability analysis and direct numerical simulation. The sectionally averaged pulsatile flow is represented with one harmonic component superimposed on a time-mean flow. We have previously identified a period-doubling global instab...
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A straight tube with a smooth axisymmetric constriction is an idealised representation of a stenosed artery. We examine the three-dimensional instability of steady flow plus an oscillatory component in a tube with a smooth 75% stenosis using both linear stability analysis and direct numerical simulation. These flows become unstable through a subcritical period-doubling bifurcation involving alt...
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We show that suitable initial disturbances to steady or long-period pulsatile flows in a straight tube with an axisymmetric 75%-occlusion stenosis can produce very large transient energy growths. The global optimal disturbances to an initially axisymmetric state found by linear analyses are three-dimensional wave packets that produce localized sinuous convective instability in extended shear la...
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A controlled ex-vivo study of a simple, sinusoidally oscillating flow in a rigid, constant-area, smooth tube, has produced significant insight into the laminar-turbulent transition phenomenon. The development of turbulence was studied by analyzing the dynamic characteristics of the transition process; i.e., the velocity, growth rate, and intermittency which describe the generation and propagati...
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This study numerically investigates turbulent pipe flow driven by a pulsating pressure gradient. While studies of laminar and turbulent pulsatile pipe flow with a single mode of oscillating pressure gradient have been carried out extensively, there is scarce literature on pulsating pressure gradients with multiple temporal Fourier modes. In many real-life engineering applications, for example, ...
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ژورنال
عنوان ژورنال: Journal of Fluid Mechanics
سال: 2007
ISSN: 0022-1120,1469-7645
DOI: 10.1017/s0022112006003740