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Author index ►Fahmida Ashraf, Taqi Ahmad Cheema, Cheol Woo Park
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The Impact of Pulsatile Spiral Flow on the Wall Deformation Characteristics and Low-Density Lipoproteins Accumulation in the Aorta
Appl. Rheol. 28:3 (2018) 35702 (10 pages) ►
Spiral blood flow in the aorta is helpful in maintaining the stability of flow, reduction in lateral forces, turbulence near walls, and shear stress index. Thus, it helps in the prevention of diseases, such as atherosclerosis and atherogenesis, in the aortic arch because of the reduced accumulation of low-density lipoproteins (LDLs). To investigate the actual physics behind the aforementioned phenomenon, we conducted a fluid-structure interaction (FSI)-based numerical simulation of the threedimensional aortic arch model under the influence of a pulsatile spiral flow. Spiral flow was introduced through the use of a mapping methodology between a spiral graft model and aortic model. The physics of time dependent pulsatile spiral turbulent flow was coupled with the structural mechanics of the aorta by using the FSI method. Results showed that the exterior interface of the aortic arch tends to rupture under the actions of centrifugal forces and secondary flow counter-rotating vortices in addition to applied pressure forces. Under systolic and diastolic conditions, the interior and exterior interfaces of the aortic arch both had small displacement, thus showing the insignificant role of velocity gradients in wall deformation. Moreover, LDL accumulation in the aorta under the influence of pulsatile spiral flow has been investigated using particle tracing methodology. The LDLs were evenly distributed in the aorta because of the influence of spiral flow. This result shows that spiral flow can contribute to the elimination of threats from diseases, such as atherosclerosis and atherogenesis.► Cite this publication as follows:
Ashraf F, Cheema TA, Park CW: The Impact of Pulsatile Spiral Flow on the Wall Deformation Characteristics and Low-Density Lipoproteins Accumulation in the Aorta, Appl. Rheol. 28 (2018) 35702.
T. A. Cheema, G. M. Kim, C. Y. Lee, J. G. Hong, M. K. Kwak, C. W. Park
Characteristics of blood vessel wall deformation with porous wall conditions in an aortic arch
Appl. Rheol. 24:2 (2014) 24590 (8 pages) ►
Blood vessels have been modeled as non-porous structures that are permeable to solutes mixed in the blood. However, the use of non-physiological boundary conditions in numerical simulations that assume atmospheric pressure at the outlet does not illustrate the actual structural physics involved. The presence of pores in the wall influences wall deformation characteristics, which may increase the risk of rupture in specific conditions. In addition, the formation of secondary flows in a curved blood vessel may add complications to the structural behavior of the vessel walls. These reservations can be addressed by a fluid structure interaction-based numerical simulation of a three-dimensional aortic arch with increased physiological velocity and pressure waveforms. The curvature radius of the arch was 30 mm with a uniform aorta diameter of 25 mm. A one-way coupling method was used between physics of porous media flow and structural mechanics. A comparison of results with a non-porous model revealed that the approximated porous model was more prone to hypertension and rupture. Similarly, the secondary flows found to be an important indicator for the vascular compliance that forced the outer aortic region to experience the largest deformation. Consequently, it is very important to use actual physiological situations of the blood vessels to reach a diagnostic solution.► Cite this publication as follows:
Cheema TA, Kim GM, Lee CY, Hong JG, Kwak MK, Park CW: Characteristics of blood vessel wall deformation with porous wall conditions in an aortic arch, Appl. Rheol. 24 (2014) 24590.
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