Numerical simulations of a diagnostic ultrasound-induced deformation of a pulmonary alveolus interface

Diagnostic ultrasound (DUS) of the lung uses high-frequency acoustic waves that interact with tissue. These waves reflect, allowing visualization of internal structures, such as air-filled alveoli and blood vessels. Due to misalignment between the gradient of the acoustic wave and material interface, baroclinic vorticity may be deposited at the tissue-air interface (air-filled alveoli). It is hypothesized that vorticity can distort the interface, potentially leading to harmful bioeffects such as hemorrhage. We conduct 3D numerical simulations of the DUS-induced deformation of an alveoli interface using the open-source Multicomponent Flow Code (MFC) [Radhakrishnan & Le Berre et al. Comp. Phys. Comm. (2024)]. MFC solves compressible flow equations using a six-equation multiphase model and, for the lung tissue, a hyperelastic material model. We present the deformation of the air-filled alveoli material interface and characterize the principal stresses within the lung tissue as a function of elastic properties, initial acoustic wave parameters, and interface geometry. Additionally, we will show elasticity inhibiting the growth of the material interface and compare with theoretical results.