Flow patterns and vortex formation mechanisms inside a human nasal cavity

Nasal airflow studies continue to face challenges due to the intricate nature of airflow and the variability in nasal cavity geometries. While significant advances have been made, much of the existing research, including studies employing Large Eddy Simulation (LES), focuses primarily on velocity magnitude fields. However, understanding nasal airflow dynamics requires examining individual velocity components, enabling a more detailed investigation of directional flow behavior and localized phenomena such as vortices. In this study, a high-accuracy LES method was used to investigate airflow patterns in the main nasal passage and around the turbinates, with particular emphasis on turbulence in these regions. The analysis revealed several previously undocumented vortices, including counter-rotating vortices in the central region of the main nasal passage caused by the interaction between the incoming airflow and the middle turbinate bone. Additionally, larger recirculation zones were identified near the cavity floor in the inferior meatus and within the lateral wall of the middle meatus. Velocity fluctuations were highest in the central nasal passage, with elevated levels also observed in the inferior and posterior sections, whereas the vestibule region exhibited high velocities but low fluctuations, indicating stable flow conditions. While this study primarily focuses on the dynamics of nasal airflow, it also attempts to explore the hypothetical implications of velocity fluctuations and vortex formation on particle transport and surgical practices. These aspects remain speculative but suggest that such dynamics could have important effects on both therapeutic strategies and surgical interventions, thus guiding future studies in these areas.