长江潮流界影响动力因子及其作用机制研究

发布时间：2018-03-16 02:21

本文选题：长江　切入点：潮流界　出处：《宁夏大学》2017年硕士论文　论文类型：学位论文

【摘要】：长江下游河段水体受上游径流与下游潮汐共同作用,运动千变万化,潮流界是其动力变化的重要表征,受多种因素影响,处于不断移动中,在各类水文情况下的变化特点极为复杂。论文在前人研究的基础上,结合实测地形资料,利用CJK3D-WEM数学模型,在非结构性网格的基础上建立了由大通至长江口的二维潮流数值模型,模型对水文资料验证结果良好,可以准确的对河道中水流运动情况进行模拟。第二、三章从潮位、潮差、涨落潮历时、潮量等多个角度对不同情况下的长江下游水体特性进行了分析,根据不同径潮流组合的计算结果讨论了在各种条件下径流、潮流对潮流界的影响作用,结果表明潮流界主要变动范围由南京附近至白茆河口附近,相比潮汐的变化,径流的洪枯季变化对潮流界的影响更大。在径流以同样速度增加时,潮流界下移速度越来越慢,在潮差以同样速度增加时,潮流界向上移动速度越来越慢。在第四章中,以江阴水道的部分河段为例剖析了顺直河道中地形对于径潮流动力分配的作用,结果表明在同一断面中,浅滩中的径潮比要小于深槽,因此浅滩中的潮流界会在深槽潮流界的上游,且在同样的径潮流变化条件下,深槽中的潮流界移动速度会比浅滩快。并且在感潮河段位于潮流界上游部分中,深槽与浅滩中的径潮比差别较大,而在潮流界的下游河段中,深槽与浅滩中径潮比的差别较小。
[Abstract]:The water body in the lower reaches of the Yangtze River is affected by the interaction of upstream runoff and downstream tide, and its movement is changeable. The tidal current boundary is an important representation of its dynamic change, which is affected by a variety of factors and is in the process of continuous movement. The variation characteristics of various hydrological conditions are very complicated. On the basis of previous studies and combined with the measured topographic data, the CJK3D-WEM mathematical model is used in this paper. On the basis of non-structural grid, a two-dimensional tidal current numerical model from Datong to Changjiang Estuary is established. The results of hydrological data verification are good, and the flow movement in the river can be accurately simulated. Second, third chapter, from tidal level, tidal range. The characteristics of the lower reaches of the Yangtze River under different conditions are analyzed from the point of view of tidal duration and tidal volume, and the effect of the tidal current on the tidal current boundary under various conditions is discussed according to the calculation results of the combination of tidal currents with different diameters. The results show that the main variation range of tidal current boundary is from Nanjing to Baimao estuary. Compared with tidal variation, flood and dry season variation of runoff has more influence on tidal current boundary. When runoff increases at the same speed, the velocity of tidal current boundary moving down becomes slower and slower. When the tidal range increases at the same speed, the upward movement of tidal current boundary becomes slower and slower. In Chapter 4th, the effect of topography on the dynamic distribution of diameter tidal current in a straight channel is analyzed by taking part of the river reach of Jiangyin waterway as an example. The results show that in the same section, the ratio of diameter to tide in the shoal is smaller than that in the deep trench, so the tidal boundary in the shoal will be upstream of the deep trench, and under the same condition of the variation of the diameter-tidal current, The moving velocity of tidal boundary in deep channel is faster than that in shoal, and in the upper part of tidal boundary, the difference of diameter to tide ratio between deep trough and shoal is great, but in the lower reaches of tidal boundary, the difference between channel and shoal is smaller.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV131.2

【参考文献】