Short communicationThe role of anisotropic expansion for pulmonary acinar aerosol deposition
Section snippets
Background
The past two decades have witnessed important efforts to resolve respiratory flows in the acinar depths, motivated in part by the prospect of predicting the fate of inhaled aerosols for therapeutic delivery (Sznitman, 2013, Tsuda et al., 2013). Parallel to the emergence of true-scale experimental acinar platforms (Fishler et al., 2013, Fishler et al., 2015), numerical simulations have served as a backbone to help advance our understanding of acinar aerosol transport given their appeal and
Methods
Drawing on recent models of multi-generational acinar networks (Hofemeier and Sznitman, 2015, Sznitman et al., 2009, Tian et al., 2015), our airway trees feature an asymmetric bifurcating structure reaching up to 6 generations with a total of 277 polyhedral alveolar units (Fig. 2) that capture the space-filling acinar morphology (Fung, 1988). Despite their simplicity and limitations (e.g. see discussion in Hofemeier and Sznitman, 2015), these domains constitute a versatile computational
Results and discussion
Modulations in the acinar expansion kinematics are anticipated to give rise to changes in airflow characteristics across the acinar network. While the underlying parabolic-like velocity profiles in the ducts and recirculation zones in alveoli remain common features across breathing motions, Fig. 2 exemplifies differences in flow magnitudes along the acinar tree. Here, 1D velocity profiles are presented at peak inspiration across the acinar ducts and alveoli (, see domain in Fig. 2
Conflict of interest statement
None declared.
Acknowledgments
The authors would like to thank Dr. R. Fishler for constructive discussions. This work was supported in part by the Israel Science Foundation (Grant no. 990/12) and the European Research Council (ERC) under the European Union׳s Horizon 2020 research and innovation programme (Grant agreement no. 677772).
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