  In this paper, investigations are conducted using Reynolds-averaged
Navier-Stokes (RANS) turbulence models to investigate the importance of
turbulence modelling for nasal inspiration at a constant flow rate of 250 ml/s.
Four different, standard turbulence models are tested in a model geometry based
on pre-operative CT images of a selected obstructive sleep-apnea syndrome
(OSAS) patient. The results show only minor differences between them.
Furthermore, the turbulence models do not give significantly different results
than a laminar flow model. Thus, the main conclusion is that effects of
turbulence are insignificant in CFD modelling of the airflow in the
pre-operative model of the upper airways of the chosen patient.
