| Autor: |
Gataulin Yakov, Smirnov Evgeny |
| Jazyk: |
English<br />Russian |
| Rok vydání: |
2021 |
| Předmět: |
|
| Zdroj: |
St. Petersburg Polytechnical University Journal: Physics and Mathematics, Vol 14, Iss 1 (2021) |
| Druh dokumentu: |
article |
| ISSN: |
2405-7223 |
| DOI: |
10.18721/JPM.14105 |
| Popis: |
Results of large eddy simulation of three-dimensional flow in a model of the blood vessel with a one-side 70% stenosis at a Reynolds number of 1800 are presented. The Germano-Lilly model was used for subgrid viscosity evaluation. It has been established that the time-averaged flow behind the stenosis is characterized by the presence of two zones of recirculation flow: (i) an extensive zone that arises just behind the stenosis and has a length of about five vessel diameters, and (ii) a relatively small zone positioned near the opposite wall at a distance of about four calibers from the stenosis center. When a high-velocity jet is formed within the stenosis region, a secondary flow also forms as a pair of counter-rotating vortices, which are similar to the Dean vortices in a curved tube flow. The vortex pair arisen in the stenosis leads to a bifurcation of the high-velocity jet and induces also a cross-flow in the reverse flow zone behind the stenosis. The cross-flow almost completely disappears at a distance of less than ten calibers from the stenosis. Hydrodynamic instabilities that are peculiar to the high-gradient mixing layer, which is formed at the boundary of the jet and the reverse flow zone, initiate turbulence occurring with formation of three-dimensional vortex structures of different scales. These structures fill the entire cross-section of the vessel near the flow reattachment point. Turbulent shear stresses are significant in magnitude only at a flow section of about four-caliber length in the vicinity of the reattachment point. Further downstream, the flow relaminarises. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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