Influence of the properties of the elasticity modulus in the nasopharynx on the hydrodynamic characteristics of the flow in the upper respiratory tract

In this study, the influence of the elasticity modulus (5-25 kPa) and inlet boundary conditions on the distribution of velocity, pressure, shear stress and strain in the upper airways was investigated using computational fluid dynamics (CFD) and fluid-structure interaction (FSI) models. Sinusoidal velocity profiles at the entrance to the nasal sinuses with oscillation amplitudes of 1.2 m/s, 2.4 m/s, 3.6 m/s were considered. The results show that the maximum value of deformation in the nasopharyngeal region occurred at a value of Young's modulus of 5 kPa, and values from 15 to 25 kPa gave deformation values lower by more than 20 % and had insignificant differences. In addition, the CFD model showed higher pressure and shear stress values than the FSI model, and the maximum velocity of the FSI models was higher than that of the CFD model. This study provides new data on the effect of modulus and inlet boundary conditions on velocity, pressure, shear stress, and strain distributions in the upper airways.