Laminar-turbulent transition in a constricted tube: Comparison of Reynolds-averaged Navier–Stokes turbulence models and large eddy simulation with experiments

Abstract

Constricted tubes appear in many engineering as well as biological systems such as blood vessels or pulmonary airways. The aim of this article is to test the ability of different turbulence models to predict the flow field and deposition of particles in a constricted tube. The constricted geometry of Ahmed and Giddens was employed to compare various numerical approaches. Two large eddy simulations and several Reynolds-averaged Navier-Stokes models were used for calculations using the Star-CCM+ commercial solver. The performance of these models was compared with the experiments and other published studies. For selected turbulence models, deposition of particles with different Stokes numbers using Lagrangian multiphase model was enabled. The results show that large eddy simulation best predicts the transition from laminar to turbulent flow in terms of mean axial velocity, and similarly does also standard low-Reynolds k-epsilon model. The comparison of deposition fractions shows substantial differences among the models, especially for the smallest particles. It was demonstrated that even a simple stenosed smooth tube is a very intricate problem for the present computational fluid dynamics models; therefore, to get reliable results, numerical models need to be validated for the same geometry and similar conditions.Constricted tubes appear in many engineering as well as biological systems such as blood vessels or pulmonary airways. The aim of this article is to test the ability of different turbulence models to predict the flow field and deposition of particles in a constricted tube. The constricted geometry of Ahmed and Giddens was employed to compare various numerical approaches. Two large eddy simulations and several Reynolds-averaged Navier-Stokes models were used for calculations using the Star-CCM+ commercial solver. The performance of these models was compared with the experiments and other published studies. For selected turbulence models, deposition of particles with different Stokes numbers using Lagrangian multiphase model was enabled. The results show that large eddy simulation best predicts the transition from laminar to turbulent flow in terms of mean axial velocity, and similarly does also standard low-Reynolds k-epsilon model. The comparison of deposition fractions shows substantial differences among the models, especially for the smallest particles. It was demonstrated that even a simple stenosed smooth tube is a very intricate problem for the present computational fluid dynamics models; therefore, to get reliable results, numerical models need to be validated for the same geometry and similar conditions.