Influence of non-submerged rigid vegetation on the flow characteristics of bend

Vegetation widely distributed in natural river shallows can change the local hydraulic characteristics of the river and the process of sediment transport. In order to understand the influence of vegetation on the flow characteristics of the bend, our experiment is aimed at the bend with rigid emergent vegetation on the convex bank under a specific flow rate, to explore the distribution law of water flow characteristics along the way when vegetation density and location are different. By establishing a generalized model of curved water flow, using ADV to collect and process the three-dimensional velocity data, and comparing the velocity distribution under the conditions with and without vegetation (vegetation density respectively ρ=0, ρ=2.2%, ρ=4.5%), we qualitatively analyze the effect of vegetation on the turbulence characteristics of the curve flow under different working conditions, and determine the structure and strength of the curve circulation. The results show that the existence of vegetation on the convex bank (0°-90° bend, evenly distributed in the quarter of the river width) can effectively weaken the circulation intensity of the bend, but the reduction effect on the convex bank area does not increase with the increase of vegetation density. The location of the dividing point of different flow direction water layers in the non-vegetation area changes with the change of vegetation density, and the distribution of vegetation also affects the circulation structure at different water depths in each section of the bend.