Flow-induced wall shear stress in abdominal aortic aneurysms: Part II--pulsatile flow hemodynamics.
In continuing the investigation of AAA hemodynamics, unsteady flow-induced stresses are presented for pulsatile blood flow through the double-aneurysm model described in Part I. Physiologically realistic aortic blood flow is simulated under pulsatile conditions for the range of time-average Reynolds numbers 50< or =Re(m) < or =300. Hemodynamic disturbance is evaluated for a modified set of indicator functions which include wall pressure (p(w)), wall shear stress (tau(w)), Wall Shear Stress Gradient (WSSG), time-average wall shear stress (tau(w)*), and time-average Wall Shear Stress Gradient WSSG*. At peak flow, the highest shear stress and WSSG levels are obtained at the distal end of both aneurysms, in a pattern similar to that of steady flow. The maximum values of wall shear stresses and wall shear stress gradients are evaluated as a function of the time-average Reynolds number resulting in a fourth order polynomial correlation. A comparison between numerical predictions for steady and pulsatile flow is presented, illustrating the importance of considering time-dependent flow for the evaluation of hemodynamic indicators.
Mechanical Engineering, Biomedical and Health Engineering, and institute for Complex Engineered Systems, Carnegie Mellon University, Pittsburgh, PA, USA.
Ender A
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Cristina H
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Amon
D001012:Aorta, Abdominal / Q000503:physiopathology*; D017544:Aortic Aneurysm, Abdominal / Q000503:physiopathology*; D001783:Blood Flow Velocity; D001794:Blood Pressure; D003198:Computer Simulation; D004548:Elasticity; D005583:Fourier Analysis; D006439:Hemodynamics; D006801:Humans; D008955:Models, Cardiovascular; D011673:Pulsatile Flow; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013599:Systole / Q000502:physiology