Pulsatile Flow in a Symmetric Sinusoidal Wavy-Walled Channel.

Abstract

Pulsatile laminar flow is examined experimentally in a two-dimensional furrowed channel with varying flow parameters. We present flow diagrams in which five flow modes are classified in terms of the Womersley number and oscillatory fraction of the flow rate for each net flow Reynolds number, on the basis of the process of vortex formation, growth and subsequent disappearance. A striking feature of pulsatile flow in the wavy-walled channel is that after the vortex ejects from the furrow, the vortex does not always disappear in the mainstream, but reattaches to the wall and eventually disappears under certain conditions, in contrast to oscillatory flow. We also show the transition to three-dimensional flow and a new flow structure in which a wave appears in the mainstream during the flow deceleration phase due to a shear layer instability.