Validation of computational fluid dynamics methodology used for human upper airway flow simulations

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Respiratory Mechanics

Background:

• Upper airway obstruction can occur in specific regions.
• Accurate fluid dynamics data is crucial for understanding airway function.

Purpose of the Study:

• To investigate airflow in the human upper airway using Computational Fluid Dynamics (CFD) simulations.
• To validate CFD predictions against experimental measurements in a physical airway model.

Main Methods:

• Anatomically accurate upper airway model created from MRI scans.
• CFD simulations using Large Eddy Simulation (LES) and various Reynolds-Averaged Navier-Stokes (RANS) models.
• Physical model fabrication via stereo lithography for pressure and velocity measurements.
• Comparison of CFD results with experimental data at a peak expiratory flow rate of 200 L/min.

Main Results:

• CFD predictions of wall static pressures favorably compared with experimental data.
• The standard k-omega turbulence model demonstrated the best agreement (approx. 20% error).
• Highest positive pressures were found retroglossal; lowest negative pressures in the retropalatal region due to airflow acceleration.

Conclusions:

• CFD simulations, particularly with the standard k-omega model, can accurately compute upper airway aerodynamic flow characteristics.
• Findings highlight pressure variations in critical airway regions, aiding in understanding obstruction mechanisms.