【摘要】 为了获得洪水期主槽-洪泛滩地系统内水流交互关系,以美国内华达州塔基河迈卡伦河段为研究对象,采用拉格朗日粒子示踪方法获得了在强、弱2种漫滩条件之下,粒子的运动轨迹、停留时间分布及空间维度上的交换频率等特点。分析结果表明,高流量有效促进了主槽水流向侧向滩地传播的范围,并且流量越大,水流在系统内的平均停留时间越短,且参与系统内水流交换的水量占总过流量的比重越大;此外,流量对不同水体间粒子发生单次交换所需行走的纵向距离影响显著,大洪水时不同水体整体交换更强烈,但局部交换相对而言弱于小洪水情况,本研究方法和结论可以为河流系统的改造和修复提供参考。更多还原

【Abstract】 In order to test the flow exchange behavior in the channel-floodplain system,a particle tracking code based on Lagrangian particle tracking method( LPTM) was used to further analysis flow interaction between the main channel and floodplains in Truckee River at Mc Carran,Nevada. The particle trajectory,the residence time distribution( RTD) and the spatial interaction frequencies were examined under two different frequency flood events. Results showed that the lateral flow traveling distance is enhanced by higher discharge.The RTD showed that the higher discharge leads to a shorter mean residence time,and the ratio of particles amount that involved in exchanges between main channel and floodplain is larger in a stronger overbank flow event. The spatial interaction frequencies revealed that the discharge has significant impacts on the longitudinal traveling distance per a single interaction of the released particles. It indicated that the overall exchange is stronger at a higher flow and the local exchange is relatively weaker than in a lower flood event. The LPTM approach can provide a reference for the river modification and restoration.更多还原