双阻隔结构下缓慢水体二维水动力特性试验研究

Experimental Research on Two-dimensional Hydrodynamic Characteristics of Slow Water Under Double Bluff Body

以景观湖泊、生态湿地等为主要代表的缓慢水体在城市建设中的重要性日益突出,如何增大水体交换区域,减缓水质恶化趋势,是我们面临的重要问题。基于粒子图像测速技术(PIV),研究了缓慢水体中双阻隔结构(岛屿)间距比、引水流量、形状对二维流场分布、水体置换率、流场平均速度的影响规律。试验结果表明,引水流量是缓慢水体流场强度变化的主控因素,水动力交换效率和水流的平均速度随引水流量的增大而增大;阻隔结构可明显改善流动范围,增加水体流动性。研究发现三棱柱和圆柱联合扰动下的水槽水体流动性最强,水体置换率最高,Q=6.8 L/min,G/D=6时达到最大置换率72.89%。试验结果将对优化景观湖泊内岛屿的布设有一定的借鉴。

Slow water bodies,mainly represented by landscape lakes and ecological wetlands,are becoming more and more important in urban construction. How to increase water exchange areas and slow down the deterioration of water quality is an important problem we are faced with. Based on particle image velocimetry(PIV)technique,the effects of spacing ratio,diversion flow rate and shape of double bluff body(islands)on two-dimensional flow field distribution,water displacement rate and average velocity of the flow field in slow water are studied.The experimental results show that the diversion flow rate is the main controlling factor for the intensity of the flow field in the slow water,and the hydrodynamic exchange efficiency and the average velocity of the water flow are proportional to the diversion flow. The bluff body can obviously improve the range of flow movement and increase the fluidity of water. It is found that the fluidity of the flume water is the strongest and the displacement rate is the highest when the prism and cylinder are disturbed together. The maximum displacement rate reaches 72.89%when Q=6.8 L/min and G/D=6. The experimental results will provide some reference for optimizing the layout of islands in the landscape lake.