Influence of artificial ecological floating beds on river hydraulic characteristics

Abstract

The artificial ecological floating bed is widely used in rivers and lakes to repair and purify polluted water. However, the water flow pattern and the water level distribution are significantly changed by the floating beds, and the influence on the water flow is different from that of aquatic plants. In this paper, based on the continuous porous media model, a moveable two-layer combination model is built to describe the floating bed. The influences of the floating beds on the water flow characteristics are studied by numerical simulations and experiments using an experimental water channel. The variations of the water level distribution are discussed under conditions of different flow velocities (v=0.1 m/s, 0.2 m/s, 0.30 m/s, 0.4 m/s), floating bed coverage rates (20%, 40%, 60%) and arrangement positions away from the channel wall (D = 0 m, 0.1 m, 0.2 m). The results indicate that the flow velocity increases under the floating beds, and the water level rises significantly under high flow velocity conditions in the upstream region and the floating bed region. In addition, the average rising water level value (ARWLV) increases significantly with the increase of the floating bed coverage rate, and the arrangement position of floating beds in the river can also greatly influence the water level distribution under a high-flow velocity condition (v ≥ 0.2 m/s).