Time-dependent vorticity field in vascular junctions

Hemodynamic related diseases and complications, such as occlusions and stenosis, are common near bifurcations and anastomosis. This work was aimed to map the details of the spatio-temporal flow characteristics near vascular junctions. Laminar to turbulent transition, flow separation, rotation and waves reflected from host artery leave characteristic spectral signature which escapes detection when only mean data is sampled. Therefore, continuous digital particle image velocimetry was used to map the flow field of vascular junctions in time. Continuous sequences of experimental images, followed by their calculated vorticity and velocity transient fields, are given as animated presentation of distensible anastomoses. High shear stress peaks and vortices were observed at the anastomosis toe. Flow reversal and separation was Reynolds dependent. Better geometrical configuration resulted in lower shear-stresses and flatter spectral distribution. This can be translated in Doppler ultrasound or sound frequencies terms and thus potentially assist clinical observations.