柔性淹没植被的排列方式对水流特性的影响

Influence of flexible submerged vegetation on flow characteristics under different arrangement patterns

采用塑料草模拟河道中的柔性淹没植被,通过室内高精度水槽试验,用三维声学多普勒流速仪对同种淹没度、不同排列方式下柔性淹没植被的水流特性进行测量研究,得到柔性淹没植被时均纵向流速、垂向紊动强度、雷诺应力沿相对水深的分布特征.结果表明:在植被层外部,两种排列方式下时均纵向流速符合"J"形分布,垂向紊动强度、雷诺应力呈递增趋势,近似线性分布;在植被层内部,梅花形排列方式下阻水效应及雷诺应力较之矩形排列明显,矩形排列方式下垂向紊动强度较之梅花形排列剧烈.

The plastic grass was used to simulate the flexible submerged vegetation in the river channel.Through the indoor high-precision flume test,the flow characteristics of the flexible submerged vegetation under the same submergence degree and different arrangement modes were measured and studied by using the three-dimensional acoustic Doppler flow meter.The distribution characteristics of the longitudinal velocity,vertical turbulence intensity and Reynolds stress along the relative water depth of the flexible submerged vegetation were obtained.The results show that outside the vegetation layer,the longitudinal velocity in both arrangements conforms to the J distribution,and the vertical turbulence intensity and Reynolds stress show an increasing trend,which is approximately linear distribution.In the vegetation layer,the water blocking effect and Reynolds stress in the plum-blossom arrangement are more obvious than those in the rectangular arrangement,and the downward turbulence intensity in the rectangular arrangement is more intense than that in the plum-blossom arrangement.