GALCIT Colloquium

I will present an overview of several ongoing research thrusts in the BioFluid Dynamics Lab, concentrating on internal and external pulsatile flows. Our studies are aimed towards: (i) understanding the physics of phonation, (ii) role of secondary flows in the vasculature, and (iii) filtration in the silver carp (Hypophthalmichthys molitrix), respectively. (i) Recent attention in our phonation studies has been focused on understanding the role of polyps (growths on the vocal folds) in altering voice quality. This has necessitated fundamental studies of 3D flow separation around surface-mounted obstacles in pulsatile flows. In addition to experiments utilizing time-resolved particle image velocimetry (TR-PIV) we have performed CFD simulations using an in-house Navier- Stokes code. These investigations are designed to examine how the structure of the shear layer and wake changes with increasing pulsatile frequency – from quasi-steady to Strouhal frequency forcing. (ii) Our studies of flow through a curved circular pipe (a canonical curved artery model, e.g. aorta) have revealed complex 3-D secondary flow vortical structures. In addition to quantifying the morphology and evolution of these structures, we have examined their imprint on the wall-shear-stress (WSS). The WSS is strongly correlated to endothelial cell biochemical response via mechanotransduction, which leads to vascular remodeling. (iii) The silver carp is an invasive fish species that threatens the Great Lakes and its multi-billion dollar per year fishing industry. This very (and bizarre) fish has outcompeted and displaced native fish species due to its propensity to reproduce quickly and its ravenous appetite satisfied by very efficient filtration feeding, consuming 20-120% of its body weight in plankton each day according to the U.S. Geological Survey. Understanding the filtration processes in silver carp is envisaged to inform bioinspired engineering