弯道局部非淹没刚性植被水流特性研究

Flow characteristics in curved open channels with partial non-submerged rigid vegetation

对180°弯道局部长有非淹没刚性植被的水流特性进行了研究.用钢筋来模拟天然河道的刚性植被,采用三维多普勒超声流速仪(ADV)分别对无植被和局部有非淹没刚性植被2种情况下的弯道水流流速场进行了测量,得到了水流沿程各断面的三维流速和紊动能分布,对2种情形的试验资料进行了比较.结果表明:植被的存在使得弯道流速重新分布,水流内部结构发生明显改变.基于等效阻力系数法,采用水深平均模型对局部非淹没刚性植被水流进行了二维数值模拟,计算结果与试验数据基本一致,表明该数值格式能预测弯道植被水流的特性.

Flow characteristics in a 180°curved open channel with partial non-submerged rigid vegeta- tion was studied. Reinforcing steel bars were used to simulate the natural vegetation. The 3D Doppler ultrasound anemometer was adopted to measure the flow velocities both in the case of vegetation andnon-vegetation. 3D velocity and turbulent kinetic energy data were obtained and compared for both ca- ses. The results show that the existence of vegetation changes the velocity distribution profile and internal flow structures in curved reach. In addition, the depth-averaged model is used to simulate thevegetation flow based on the equivalent resistance coefficient method. The calculation results are in good agreement with the experimental data, which shows that the numerical format can effectively predict the flow characteristics in curved open channels.