Secondary Flow and Upstream Dynamics in Double Bifurcation Model

Abstract

Flow behavior in bifurcation models is of great importance to health risk assessments and pulmonary drug delivery. This is particularly true of secondary flow behavior in multi-bifurcation models. Previously, both numerical and experimental methods have shown that four-vortex secondary flow structures can develop in the cross-sections of grand-daughter branches. This work shows that the development of secondary flow in the grand-daughter tubes is due to local stretching of vortex lines in the upstream DT. Scaling arguments have been used to derive two critical parameters governing this particular vorticity transport problem. A simple model for vorticity generation and transport is proposed, taking into account the geometric limitations imposed by the rigid walls of the tubes.