Large-Eddy Simulation of Flow in a Tube with an Axisymmetric Stenosis

J.J. Beech-Brandt, W.J. Easson, and P.R. Hoskins (UK)


Hemodynamics,turbulence modelling,arterial blood flow


Understanding flow in stenosed arteries is crucial to our un derstanding of the progression of arterial disease. Flow in diseased arteries is likely to be transitional, and possibly even turbulent, in certain parts of the cardiac cycle. How ever, current turbulence models have proved inadequate for accurately predicting flow distal to the stenosis, even in steady simulations. In this paper, a large-eddy simulation (LES) model is used for steady flow in a 75% area reduc tion vessel at a variety of Reynolds numbers. Parabolic velocity profiles are applied at the inlet, and a pressure boundary condition is used at the outlet. Laminar, tran sitional and turbulent regimes are all present. Results from this study are compared to previous computational work, using two-equation turbulence models, with favourable re sults. The results are also validated against existing exper imental work. This study shows that the LES model gives better marginally better results at the low Reynolds num ber evaluated. However, the improvement is modest when compared to the transitional version of the k − ω model. Ongoing work suggest however that LES is a significant improvement at moderate to high Reynolds number found in the cardiovascular system.

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