Experimental investigation of hemodynamics in abdominal aortic aneurysm

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2022-9

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Fathipour, Amirhossein

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Abdominal aortic aneurysm (AAA), the enduring enlargement of the aorta, is a serious clinical condition with a very high mortality rate when it ruptures. Even though the precise causes of the dilation and rupture mechanisms of the aorta are still unknown, flow-related structures inside the AAA, including vortex formations and wall shear stresses, are associated with these mechanisms. The present study aims to characterize the flow patterns and their evolutions in two aneurysm models, simplified elliptic geometry and patient-specific geometry, under physiological flows. For the characterization, an optical velocity measurement technique, 2-D planar Particle Image Velocimetry (PIV), was employed in an In-vitro physiological flow set-up. For the simple model, the center plane was used for the measurement plane, whereas for the patient-specific model, due to its complex geometry, the flow fields at three different planes were quantified. The phase-averaged velocity, vorticity, and swirling strength ( ci) contours were constructed along with the streamline patterns. The results indicate that a vortex ring and the formation of two additional vortical structures are apparent in the simplified aneurysm model during the physiological cycle. In the patient-specific aneurysm model, the flow is highly 3-D, and relatively weak vortex formations are evident without a clear indication of a vortex ring. Different recirculation regions at different instants of the physiological vi cycle are also apparent. Further studies are needed for a complete understanding of flow structure in the patient-specific aneurysm model.

Subject Keywords

Abdominal Aortic Aneurysm, Vortex, PIV

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https://hdl.handle.net/11511/99473

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Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

A. Fathipour, “Experimental investigation of hemodynamics in abdominal aortic aneurysm,” M.S. - Master of Science, Middle East Technical University, 2022.