The Effect of Neglecting Transient Flow in Nasal Cavity CFD Simulations

This paper investigates the influence of neglecting transient airflow effects in computational fluid dynamics (CFD) simulations of the human nasal cavity. A realistic three -dimensional geometry reconstructed from computed tomography (CT) data was analysed using ANSYS Fluent. Unsteady Reynolds -Averaged Navier-Stokes (URANS) simulations employing the realizable k-w turbulence model with enhanced wall treatment were performed over one full breathing cycle and compared with a series of steady -state simulations representing discrete time instants of the same cycle. The comparison focuses on total pressure loss and wall shear stress (WSS), which are key quantities for the assessment of breathing effort, mucosal stimulation and olfactory airflow. The results demons trate that steady simulations systematically underestimate peak wall shear stress and partially underestimate pressure loss, particularly during flow acceleration and deceleration phases. The study confirms that transient modelling is essential for realist ic and clinically relevant CFD analysis of nasal airflow.