The effect of substrate stretching on the thin-film distribution near an alveolar corner
Abstract
Because the lung contains an extensive and highly-curved air--liquid interface, surface tension forces play a central role in respiration. Anatomical studies have shown that the lung's liquid-film lining accumulates in the corners of polyhedral alveoli (the terminal airway units). We study the thin-film distribution near an alveolar corner by numerically integrating a model equation. In the absence of substrate stretching, the film attains a quasi-steady form in which a satellite drop drains slowly into a corner puddle. Canonical `Hammond draining' dynamics are observed, with the (perturbation) pressure varying rapidly and monotonically between the puddle and droplet. When the substrate is stretched, to mimic the effect of breathing, the pressure variation is no longer monotonic. We discuss the origin and implications of the modified pressure distribution and attempt to identify asymptotic scaling regimes.
- Publication:
-
APS Division of Fluid Dynamics Meeting Abstracts
- Pub Date:
- November 2003
- Bibcode:
- 2003APS..DFD.EE006C