  Computational fluid dynamics (CFD) is a useful tool for prediction of
turbulence in aerodynamic and biomedical applications. The choice of
appropriate turbulence models is key to reaching accurate predictions. The
present investigation concentrated on the comparison of different turbulence
models for predicting the flow field downstream of a constricted pipe. This
geometry is relevant to arterial stenosis in patients with vascular diseases.
More specifically, the results of Unsteady Reynolds-Averaged Navier-Stokes
(URANS) and scale resolving simulation (SRS) turbulence models such as Large
Eddy Simulation (LES) and Detached Eddy Simulation (DES) were compared with
experimental measurements. Comparisons included the mean flow and fluctuations
downstream of the constriction. Results showed that the LES model was in better
agreement with the velocity measurements performed using a Laser Doppler
Anemometry (LDA). In addition, although URANS models predicted a wake region
size and mean flow velocities comparable to SRS turbulence models, no
small-scale vortical structures can be observed in the URANS solution due to
the nature of these models. Modeling of these structures would, however, be
helpful when more detailed flow behavior is needed such as in studies of
acoustic sources. Hence, LES would be an optimal turbulence model for the flow
under consideration, especially when sound generation would be of interest.
