Diseases Involving the Central Bronchi: Multidetector CT for Detection, Characterization, and Differential Diagnosis

Purely elastic instabilities in the airways and oral area

“…Order of magnitude of dimensional parameters, thickness of the viscoelastic liquid (R), thickness of the deformable muscle layer (HR), relaxation time of the viscoelastic liquid (λ), air speed past the liquid (V a ) and the shear modulus of the deformable layer (G) for various parts of the airways and oral area relevant during breathing, talking, coughing and sneezing actions. For the oral area, the data are from Collins & Dawes (1987) Shields & Jeffery (1987) and for bronchi and bronchioles from Hwang et al (1969), Wang et al (2011), Theriault et al (2018 and Lai et al (2009). Other properties such as density and viscosity of the liquids are ∼10 3 kg m −3 and ∼10 2 -10 −3 Pa s, respectively and air-liquid interfacial tension is ∼10 −1 -10 −2 N m −1 (Hwang et al 1969;Lai et al 2009;Hamed & Fiegel 2014;Chen et al 2019).…”

“…described by Trefethen (2000) and Schmid & Henningson (2001). We use the polyeig MATLAB routine to solve the constructed, generalised eigenvalue problem given by (3.7).…”

“…These instabilities could play a role in airway closure or in the formation of fluid particles (i.e. droplets and aerosols) expelled from a person during breathing, talking, coughing and sneezing (Tang et al 2012(Tang et al , 2013Theriault et al 2018;Mittal, Ni & Seo 2020), which may lead to the spread of respiratory diseases.…”