| Autor: |
Liu, Mengyang, Huai, Wenxin, Ji, Bin |
| Předmět: |
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| Zdroj: |
Physics of Fluids; Mar2021, Vol. 33 Issue 3, p1-17, 17p |
| Abstrakt: |
The flow around submerged canopy patches with finite sizes plays a critical role in the sediment deposition and vegetation evolution. In this study, the submerged canopy patch was modeled as a porous array with a diameter D and a height h consisting of N rigid cylinder elements with a diameter d and exposed to a fully developed turbulent open channel flow with a depth H. High-resolution numerical simulations were conducted to investigate the effects of array density (0.021 ≤ Φ = Nd2/D2 ≤ 1) on mean and instantaneous flow fields and three-dimensional coherent structures by fixing the aspect ratio h/D at 1 and the submergence H/h at 2. The results showed that as the array became denser, the streamwise bleeding flow decreased while the lateral and vertical bleeding flow increased. When Φ ≥ 0.098, the group behavior of the array became significant: (1) a vertical shear layer was formed at the top of the array, and the downflow behind the array increased with Φ; (2) horseshoe vortex systems formed around the upstream base of the array; and (3) although no patch-scale vortex shedding was observed in the vorticity field in all simulated cases, there was a dominant dimensionless frequency (StD) in the power spectrum of the lateral velocity, varying from 0.1614 to 0.1913. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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