Experimental study of aortic flow in the ascending aorta via Particle Tracking Velocimetry

Abstract

A three-dimensional, pulsatile flow in a realistic phantom of a human ascending aorta with compliant walls is investigated in vitro. Three-Dimensional Particle Tracking Velocimetry (3D-PTV), an image-based, nonintrusive measuring method is used to analyze the aortic flow. The flow velocities and the turbulent fluctuations are determined. The velocity profile at the inlet of the ascending aorta is relatively flat with a skewed profile toward the inner aortic wall in the early systole. In the diastolic phase, a bidirectional flow is observed with a pronounced retrograde flow developing along the inner aortic wall, whereas the antegrade flow migrates toward the outer wall of the aorta. The spatial and temporal evolution of the vorticity field shows that the vortices begin developing along the inner wall during the deceleration phase and attenuate in the diastolic phase. The change in the cross-sectional area is more distinct distal to the inlet cross section. The mean kinetic energy is maximal in the peak systole, whereas the turbulent kinetic energy increases in the deceleration phase and reaches a maximum in the beginning of the diastolic phase. Finally, in a Lagrangian analysis, the temporal evolution of particle dispersion was studied. It shows that the dispersion is higher in the deceleration phase and in the beginning of the diastole, whereas in systole, it is smaller but non-negligible.

Fluctuations around mean walking behaviors in diluted pedestrian flows

“…To reduce noisy fluctuations from 3D reconstruction and head detection, we adopt the Savitsky-Golay smoothing filter [24], common in the particle-tracking velocimetry community (cf., e.g., [25,26]). We employ a local quadratic approximation based on a symmetric window having width equal to seven time samples.…”

Particle Margination and Its Implications on Intravenous Anticancer Drug Delivery

“…Blood flow in the body is generally considered as laminar flow, although the flow can become turbulent under certain conditions, such as in the ascending aorta (17). In laminar flow, a simple Newtonian fluid exhibits a parabolic velocity profile and the flow is composed of a multitude of fluid layers, oriented parallel to one another in the flow direction, that travel smoothly without disruption alongside one another.…”

Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow

“…Since then, many improvements have been made on the 3D-PTV algorithm and experimental setup [21][22][23][24] . With these accomplishments and previous works, the system has been successfully used to study various fluid phenomena such as large-scale fluid motion in a domain of 4 m x 2 m x 2 m 25 , indoor airflow field 26 , pulsatile flows 27 and aortic blood flow 28 .…”

“…An alternative to expensive setups with multiple high-speed cameras is the view splitter, proposed by Hoyer et al 35 for the use of 3D-PTV and recently applied by Gulean et al 28 for the biomedical applications. The view splitter consists of a pyramid-shaped mirror (hereon primary mirror) and four adjustable mirrors (hereon secondary mirror).…”