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Analyzing Mixing Inhomogeneity in a Microfluidic Device by Microscale Schlieren Technique
Published on: June 12, 2015
Using Lagrangian coherent structures to analyze fluid mixing by cilia
Sarah Lukens1, Xingzhou Yang, Lisa Fauci
1Department of Mathematics, Tulane University, 6823 St. Charles Avenue, New Orleans, Louisiana 70118, USA. slukens@math.tulane.edu
Chaos (Woodbury, N.Y.)
|April 8, 2010
Summary
This study models lung airway fluid flow using a computational cilium. It reveals a barrier structure that separates fluid near the cilium from downstream flow, enabling complex mixing.
Area of Science:
- Fluid dynamics
- Biophysics
- Computational biology
Background:
- Understanding fluid flow in the lung's airway surface liquid is crucial for respiratory health.
- Cilia-driven mucus transport is a key physiological process in the airways.
Purpose of the Study:
- To computationally model and analyze fluid flow generated by a motile cilium in the lung airways.
- To investigate the role of a mucus layer in modulating cilium-driven fluid dynamics and mixing.
Main Methods:
- Developed a computational model of an internally actuated cilium interacting with a mucus layer (linear elastic elements) and viscous fluid.
- Employed an immersed boundary method to capture the coupled system's evolution.
- Utilized Eulerian velocity fields to compute finite-time Lyapunov exponent fields and identify Lagrangian Coherent Structures (LCSs).
Main Results:
- Identified a barrier structure (LCS) separating fluid recirculation near the cilium from downstream advection.
- Observed complex mixing due to periodic stretching and folding of the fluid.
- Compared flow structures with and without a mucus load, highlighting the mucus layer's influence.
Conclusions:
- The study elucidates the intricate fluid dynamics and mixing mechanisms driven by cilia in airway mucus.
- Lagrangian coherent structures effectively visualize flow barriers and mixing regions.
- The presence of a mucus layer significantly alters cilium-induced flow patterns.
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