滩槽交界带不同植被布置方式对水动力特性影响的数值研究

Numerical Study on Influence of Different Vegetation Arrangements on Hydrodynamic Characteristics in Junction Zone Between Floodplain and Channel

为研究滩槽交界带不同植被布置方式对水动力特性的影响,基于Delft3D-FM构建了考虑二次流影响的二维水动力模型,分析了植被平行布置、交错布置、无植被工况下河道断面速度分布、二次流强度和河底剪切应力。结果表明,与无植被工况相比,植被增加了滩槽间动量交换,布置有植被的河道主槽流速增大,植被区流速减小,植被的存在减小了植被区的二次流强度,增大了主槽的二次流强度和滩槽交界带剪切应力;交错布置植被会明显增大主槽二次流强度。

In order to discuss the influence of different vegetation arrangements on the hydrodynamic process in the junction zone between floodplain and main channel,this paper constructs a two-dimensional hydrodynamic model based on Delft3D-FM,which considers the influence of secondary flow.The changes of hydrodynamic characteristics,such as velocity distribution,secondary flow intensity and bed shear stress,are analyzed under the conditions of parallel vegetation arrangement,staggered vegetation arrangement and no vegetation.Comparison with no vegetation conditions,vegetation has increased momentum exchange between floodplain and channel,the flow velocity in the main channel of a river with vegetation increases,while the flow velocity in the vegetation area decreases.The presence of vegetation increases the secondary flow and shear stress in the main channel.The staggered arrangement of vegetation significantly increases the secondary flow in the main channel and the bed shear stress.