黄河下游滩区含植物水流运动及阻力试验研究

Study on the hydrodynamic and resistance characteristics of open-channel flow with vegetation in the floodplain of the Lower Yellow River

含植物水流运动规律是研究黄河下游滩区防洪的重要内容。通过开展水槽试验,测量不同水深、比降、含沙量条件下的流速分布,研究了黄河下游滩区代表性植物作用下的水流动力特性及阻力变化规律。研究结果表明,植物在非淹没情况下,纵向流速随相对水深增加,表现为先增后减;在淹没情况下,纵向流速沿垂向呈三区“S”形分布特性;相对紊动强度的沿垂线分布特点与纵向流速基本一致,但含沙量越大,水流纵向紊动强度越小。在相同比降条件下,植被糙率随佛汝德数的增加而减小;而佛汝德数一定时,植被糙率与比降成正比;相同比降条件下的植被糙率随含沙量的增加而减小。

Study on the characteristics of open-channel flow through vegetation is an important content of flood control in the floodplain of the Lower Yellow River.A flume experiment was conducted in this paper,through measuring the flow velocity distribution under different water depth,slope and sediment concentration.Results show that under the non-inundation condition,the longitudinal velocity increased first and then decreased with the increasing relative water depth.In the case of inundation condition,the velocity presented a three-zone"S"distribution along the vertical direction.The vertical distribution of relative turbulence intensity were generally consistent with the velocity,and it became smaller with a larger sediment concentration.Vegetation roughness decreased with Froude number under the same flow slope.It was proportional to the flow slope under the same Froude number;and the vegetation roughness decreased as sediment concentration increased.