Experimental analysis of a human aorta via particle imaging and tracking velocimetry

The aorta is the large artery leaving the heart. Under normal conditions the flow is claimed to be laminar, but it may also become turbulent. Turbulence and the associated increased shear stress are believed to be associated mostly with pathological blood flow phenomena. Although in the last decades there have been many scientific investigations on the flow characteristics in a human, it is still unknown whether and under what circumstances aortic flow becomes turbulent. In this study, the main aim is to advance the hydrodynamic understanding of aortic flows. To achieve this, transition from laminar to turbulent flow in an elastic and transparent anatomically accurate replica of a human aorta is analyzed. In this paper, we explain our experimental approach and discuss our preliminary results. Particle Imaging Velocimetry (PIV), an image-based non intrusive measuring technique is applied to a pathological human aorta replica with a large inlet diameter of 45 mm. In this paper 2D-PIV results on the flow characteristics in the aorta are reported. For the future second step of the project we plan to measure 3-D flow characteristics through 3D-PTV (Particle Tracking Velocimetry). In a later stage of the project, PIV and 3D-PTV measurements will be compared to velocity data obtained by Magnetic Resonance Imaging (MRI) in the same replica, e.g., [7], [1]. The purpose of this comparison is to validate the MRI technique. In the final phase of the project, 3D-PTV will be employed to investigate the flow beyond the capabilities of MRI. In particular, we plan to measure velocity fluctuations and also velocity derivatives such as vorticity or strain.