Simulation of laminar-to-turbulent transitional flow with application to Obstructive Sleep Apnea

Computational fluid dynamic (CFD) simulations may help to understand the pathophysiology of the Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS) by modelling the abnormal airflow in the human upper airway system. It is therefore necessary to accurately reproduce the transition from laminar to turbulent flow occurring in that area. It is examined whether this behaviour can be captured by a computation without turbulence modelling on a moderately fine computational grid. Simulation results are compared to experimental data of a similar biomedical task, a stenosis in an artery, and the simulation in usage of a low Reynolds Number K -ε turbulence model of previous open literature. It shows up that although the simulation using no turbulence modelling gives a well approximation to the experimental data, the low Reynolds Number K -ε turbulence model performs superior in predicting the transitional flow regime.