Imperial College London


Faculty of EngineeringDepartment of Aeronautics

Professor of Computational Fluid Mechanics



+44 (0)20 7594 5052s.sherwin Website




313BCity and Guilds BuildingSouth Kensington Campus






BibTex format

author = {Cookson, AN and Doorly, DJ and Sherwin, SJ},
doi = {10.1007/s10439-009-9636-y},
journal = {Ann. Biomed. Engrg.},
pages = {710--721},
title = {Mixing through stirring of steady flow in small amplitude helical pipes},
url = {},
volume = {37},
year = {2008}

RIS format (EndNote, RefMan)

AB - In this paper we numerically simulate flow in a helical tube for physiological conditions using a co-ordinate mapping of the Navier–Stokes equations. Helical geometries have been proposed for use as bypass grafts, arterial stents and as an idealized model for the out-of-plane curvature of arteries. Small amplitude helical tubes are also currently being investigated for possible application as A–V shunts, where preliminary in vivo tests suggest a possibly lower risk of thrombotic occlusion. In-plane mixing induced by the geometry is hypothesized to be an important mechanism. In this work, we focus mainly on a Reynolds number of 250 and investigate both the flow structure and the in-plane mixing in helical geometries with fixed pitch of 6 tube diameters (D), and centerline helical radius ranging from 0.1D to 0.5D. High-order particle tracking, and an information entropy measure is used to analyze the in-plane mixing. A combination of translational and rotational reference frames are shown to explain the apparent discrepancy between flow field and particle trajectories, whereby particle paths display a pattern characteristic of a double vortex, though the flow field reveals only a single dominant vortex. A radius of 0.25D is found to provide the best trade-off between mixing and pressure loss, with little increase in mixing above R = 0.25D, whereas pressure continues to increase linearly.
AU - Cookson,AN
AU - Doorly,DJ
AU - Sherwin,SJ
DO - 10.1007/s10439-009-9636-y
EP - 721
PY - 2008///
SP - 710
TI - Mixing through stirring of steady flow in small amplitude helical pipes
T2 - Ann. Biomed. Engrg.
UR -
UR -
UR -
UR -
VL - 37
ER -