Vorticity

Physics

Reynolds number

Vortex

Cylinder

Open-channel flow

Flow (mathematics)

Mathematics

Mechanics

Vortex shedding

Turbulence

Dimensionless quantity

Geometry

Physics of Fluids

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 upstr...

Characteristics of the flow structures through and around a submerged canopy patch