ORIGINAL RESEARCH article
Front. Physiol.
Sec. Respiratory Physiology and Pathophysiology
Volume 16 - 2025 | doi: 10.3389/fphys.2025.1666826
This article is part of the Research TopicTranslating Biomechanics of the Human Airways for Classification, Diagnosis and Treatment of Pulmonary DiseasesView all 7 articles
Computational Modeling of Cough-Induced Droplet and Mucosal Film Dynamics in the Upper Airway for Pulmonary Disease Classification
Provisionally accepted
- The University of Central Florida, Orlando, United States
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Cough-generated droplets are critical in the transmission and progression of respiratory diseases. This study investigates droplet formation and transport in the upper airway during a cough to improve understanding of their biomechanical behavior and explore their potential for non-invasive classification of airway diseases. A computational fluid dynamics model is employed to simulate a transient, droplet-laden cough in a CT-derived human upper airway, using an experimentally acquired cough profile. The method incorporates mucus film dynamics using the Eulerian Wall Film (EWF) model and droplet transport using the Discrete Phase Model (DPM). Three mucus thicknesses—healthy baseline (Type I), intermediate pathological thickening (Type II), and advanced pathological thickening (Type III)—and three viscosity levels for Type II: baseline viscosity (Type II-A), intermediate viscosity (Type II-B), and high viscosity (Type II-C) are considered. These cases represent a progressive increase in both mucus thickness and viscosity, encompassing a spectrum of respiratory conditions. The results show that a 50% increase in mucus thickness (from 20 µm to 30 µm) results in 4.3-fold increase in exhaled droplet count and a 20% increase in mean droplet size. Conversely, a 50% increase in mucus viscosity reduces exhaled droplet count by 2.7-fold while increasing mean droplet size by 9%. Absorbed droplets, which remain within the airway, exhibit similar trends; however, as they are not measurable non-invasively, their diagnostic utility is limited. These findings highlight the role of mucus in droplet dynamics and support the potential of exhaled droplet size distribution as a diagnostic biomarker for airway disease.
Keywords: cough1, Cough droplet2, Mucus3, respiratory disease4, computational fluid dynamic5, Non-invasive diagnostics6
Received: 15 Jul 2025; Accepted: 04 Sep 2025.
Copyright: © 2025 Ilegbusi, Khan and Hoffman. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Olusegun J Ilegbusi, The University of Central Florida, Orlando, United States
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