不同布设方式的生态浮床对水流结构影响研究

生态浮床是一种应用广泛的水质净化水体修复技术。在河道中布设生态浮床会干扰水流结构，影响河道行洪排涝能力。本文区分低透水性浮床主体区和高透水性浮床根系区，运用两层式固定多孔介质域概化生态浮床，构建生态浮床不同布设方式的水槽三维水动力数学模型，对比分析无浮床、浮床不同间距串联或交错排列等14种工况的水槽水动力特性及其变化规律。布设浮床后浮床上游水面壅高、下游水面先局部降低后恢复，浮床段流速垂线分布呈“纺锤形”且平均流速和紊动能明显增大。相较于串联排列，交错排列方式对水流结构影响程度较大，且水位、流速、紊动能等水动力参数随浮床间距的变化趋势相异。因此，考虑对洪水位的壅高及增强水流紊动强度利于污染物扩散，实际应用中需结合研究成果合理选择生态浮床的布设方式。

Influence of different arrangements of ecological floating beds on flow structure

Ecological floating bed is a kind of technology to purify water quality and restore water environment, which is widely used around the world. But ecological floating bed can also disorder flow structure and affect the flood discharge capacity of rivers. In this paper, the main part of the floating bed with low permeability and its root zone with high permeability are generalized as a two-layer continuous porous media domain in a three-dimensional hydrodynamic model of flume,by which fourteen arrangements of ecological floating bed in the water channel are built to study the influences of the floating beds on the water flow characteristics. According to the results, ecological floating bed causes heading up of water level along the flow expect the local area where water level drops. Distribution of vertical velocity in the bed region is spindle-shaped. Besides, average velocity and turbulent kinetic energy also increase. Compared with tandem-arrangement, the staggered-arrangement has a greater impact on the flow structure, and the tendencies of water level, velocity, turbulent kinetic energy are related to the different space between ecological floating beds. Under different circumstance,different arranging formats of the ecological floating beds should be applied to control the heading up of the water level and the intensity of flow turbulence.