青草沙水库流

发布时间：2018-02-26 16:18

本文关键词： 青草沙水库三维流场滞留时间盐水入侵来源数值计算　出处：《华东师范大学》2014年硕士论文　论文类型：学位论文

【摘要】：本文通过现场观测、数值模拟和动力分析的方法,对长江河口青草沙水库库内的流场、滞留时间和取水口盐水入侵来源开展研究。主要成果如下： (1)运用坐底式观测系统,对青草沙水库库内的水位、速流向剖面、氯度、水温、浊度和波浪进行了冬季和夏季持续1月定点观测,获得了大量第一手的库内水文资料。观测结果表明,库区的水流流速整体较小：青草沙垦区北侧水道的流速流向对风应力较为敏感；南侧水道的流速较北侧的流速大,且在上游取水口开闸取水的时间段内流速会出现突然变大的情况,水流主要通过垦区南侧水道流向下游输水口；水库东侧的流速比水库西侧流速小,上游引水闸启闭对该处的流场没有明显影响。 (2)建立了高分辨率的青草沙库内和库外长江河口两套三维数值模式。运用实测资料对模式计算的水位、流速、流向、盐度进行验证,验证结果良好。 (3)利用库内水动力三维数值模式探究库内的流场结构和生成机制。模拟在恒定取水和供水流量情况下的吞吐流,冬、夏季不同盛行风作用下的风生流,以及吞吐流和风生流共存下总流场。模式计算结果表明：在稳定状态下吞吐流是由取水口和供水口流量的惯性驱动产生的。在水库的西区青草沙垦区南侧的流速和流量大于北侧的流速和流量。在水库的中东区,吞吐流主要沿南侧向东流动,中部和北侧流速很小。在纯风应力驱动的情况下,风应力驱动表层水体流动,水体向下风向堆积,导致上风向水位下降,下风向水位上升,形成反向的水位梯度力,驱动底层水体由下风向向上风向流动。因此,表层水库中的风生流在表层和底层是反向的,底层实为补偿流,流场结构满足流体运动的守恒性和连续性。在吞吐流和风生流共存情况下,总流场除了取水口附近水库西北水域和供水口附近小范围内外,其它区域流场与仅由风应力产生的风生流几乎一致。这表明青草沙水库的流场由风生流控制,吞吐流量值相对较小。 (4)利用库内水动力三维数值模式分析青草沙水库的滞留时间。由于水库的面积大,滞留时间存在空间上的差异性,本文将其划分成6个区域来探讨其水体滞留时间。针对不同的动力状况设计5组数值试验,计算和分析水库的滞留时间。数值计算结果表明,在夏季一般情况下(东南风5m/s,上闸两潮进水,下闸口两潮排水,供水500万吨/天,自由水位),各区水体滞留时间存在较大差异,中南区最长可达30天以上,西南区最短约为6.25天。整个水库表层平均滞留时间约为25.21天,中层平均滞留时间约为25.21天,底层平均滞留时间约为25.33天。无风有利于水库的水体置换；东北风相对于东南风(夏季盛行风)更加不利于水库的水体交换；在夏季盛行风的条件下增加供水量,水体的滞留时间明显缩短；低水位运行,上游闸进水时间、下游闸出水流量均减小,库内水动力减弱,使得滞留时间变长,对水库的水体置换不利。 (5)应用改进的长江河口盐水入侵三维数值模式,研究青草沙水库取水口盐水入侵来源。计算结果表明,在一般动力条件下小潮后中潮、大潮、大潮后中潮和小潮期间北支倒灌占青草沙水库取水口表层盐水入侵比例分别为69.5%、89.3%、98.5%和99.5%,占底层盐水入侵比例分别为34.9%、88.9%、98.5%和99.5%。除了小潮后中潮期间底层盐水入侵来源主要来自下游外海(占65.1%),青草沙水库取水口表层和底层盐水入侵来源主要来自北支盐水倒灌,尤其是大潮后中潮和小潮期间几乎全部来自北支盐水倒灌。
[Abstract]:Through field observation, analysis and numerical simulation methods of power flow, the Yangtze River estuary grass sand water database, residence time and water intake sources of saltwater intrusion is studied. The main results are as follows:
(1) the use of bottom sitting on the grass sand water level observation system, the database of water flow, velocity profile, chlorine, temperature, turbidity and wave of winter and summer last January fixed observation to obtain a large number of first-hand reservoir hydrological data. The observation results show that the flow velocity in the whole small grass sand: the flow of water in the north wind stress sensitive; on the south side of the channel is on the north side of the flow velocity, and the time of upstream water intake gate water flow velocity will appear suddenly becomes large, the flow through the flow of water in the South East of the reservoir downstream water outlet; the flow velocity of small reservoir than on the west side and upstream water diversion sluice hoist flow on the no effect.
(2) two sets of three-dimensional numerical models of high resolution Qing Cao Sha Kou and out of the Changjiang Estuary were established. The measured data were used to verify the water level, velocity, direction and salinity of the model calculated, and the results were good.
(3) to explore the flow structure and formation mechanism in the library library using the hydrodynamic numerical model. The simulation throughput at constant intake and water flow under the condition of the flow, winter, summer prevailing winds under the action of the current flow, and the throughput of flow and total flow. The coexistence of wind-driven current
The calculation results show that the model in the steady state throughput flow is generated by the water intake and water outlet flow inertia. The drive is greater than the flow rate and flow velocity and flow in the reservoir on the north side of the Western reclamation area on the south side of the Qingcaosha Reservoir. In the Middle East region, the main inflow flow eastward along the south side, central and North flow velocity small.
In the pure wind stress driven wind stress driven surface water flow, water accumulation leads to wind down the wind direction, the water level dropped, the rising water level to form a reverse of the wind, the water level gradient force, driven by the wind to the bottom water on the wind flow. Therefore, the surface water pool in the wind-driven current in the surface and the bottom layer is reverse, the bottom is compensation flow, flow structure to satisfy the conservation and continuity of fluid motion.
In terms of flow and current flow under the condition of the coexistence of the total flow except near the water intake and water reservoir near the northwest waters small range, and other areas of flow only by wind stress generated by wind-driven current is almost the same. This shows that the flow field of Qingcaosha Reservoir controlled by wind flow, relatively small flow throughput value.
(4) analysis of the retention time of Qingcaosha Reservoir with reservoir hydrodynamic numerical model. Because of the reservoir area, the residence time has spatial differences, this paper will be divided into 6 areas to explore the residence time of the water. According to the dynamic status of different design 5 groups of numerical experiments, the calculation and analysis of reservoir the retention time.
The numerical results show that in the summer under normal circumstances (southeast wind 5m/s, on the gate of the two tidal inlet, under the two tide gate drainage, water supply 5 million tons / day, free water), the water retention time differences, the central region is more than 30 days, the southwest region of the shortest in about 6.25 days. The whole reservoir the average residence time of about 25.21 days, the middle average residence time is about 25.21 days, the average residence time of about 25.33 days. There are no water replacement for reservoir; northeast wind southeast wind (relative to the prevailing wind in summer) more is not conducive to the reservoir water exchange; increase the amount of water supply in the summer wind under the conditions of detention shorten the time of water; the low water level, water upstream gate time, downstream sluice water flow decreased, water base power weakened, the residence time becomes longer, unfavorable to the reservoir water replacement.
(5) the application of improved saltwater intrusion in the Changjiang Estuary three-dimensional numerical model of Qingcaosha Reservoir water intake sources of saltwater intrusion. The results show that in general dynamic conditions in neap tide, tide, tide and tide in 89.3% after during the neap tide from the North Branch for Qingcaosha Reservoir surface water intake of salt water intrusion rates were 69.5% and, 98.5% and 99.5%, accounting for the proportion of saltwater intrusion were 34.9%, 88.9%, 98.5% and 99.5%. after the tide during the neap tide in addition to the underlying sources of saltwater intrusion are mainly from the downstream coast (65.1%), Qingcaosha Reservoir intake surface layer and the underlying sources of saltwater intrusion mainly from saltwater spilling over from the North Branch, especially after the tide tide and during the neap tide almost entirely from the saltwater spilling over from the North Branch.

【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV697

【参考文献】