本文關(guān)鍵詞： 青草沙水庫(kù) 三維流場(chǎng) 滯留時(shí)間 鹽水入侵 來(lái)源 數(shù)值計(jì)算　出處：《華東師范大學(xué)》2014年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：本文通過(guò)現(xiàn)場(chǎng)觀測(cè)、數(shù)值模擬和動(dòng)力分析的方法,對(duì)長(zhǎng)江河口青草沙水庫(kù)庫(kù)內(nèi)的流場(chǎng)、滯留時(shí)間和取水口鹽水入侵來(lái)源開(kāi)展研究。主要成果如下： (1)運(yùn)用坐底式觀測(cè)系統(tǒng),對(duì)青草沙水庫(kù)庫(kù)內(nèi)的水位、速流向剖面、氯度、水溫、濁度和波浪進(jìn)行了冬季和夏季持續(xù)1月定點(diǎn)觀測(cè),獲得了大量第一手的庫(kù)內(nèi)水文資料。觀測(cè)結(jié)果表明,庫(kù)區(qū)的水流流速整體較�。呵嗖萆硥▍^(qū)北側(cè)水道的流速流向?qū)︼L(fēng)應(yīng)力較為敏感；南側(cè)水道的流速較北側(cè)的流速大,且在上游取水口開(kāi)閘取水的時(shí)間段內(nèi)流速會(huì)出現(xiàn)突然變大的情況,水流主要通過(guò)墾區(qū)南側(cè)水道流向下游輸水口；水庫(kù)東側(cè)的流速比水庫(kù)西側(cè)流速小,上游引水閘啟閉對(duì)該處的流場(chǎng)沒(méi)有明顯影響。 (2)建立了高分辨率的青草沙庫(kù)內(nèi)和庫(kù)外長(zhǎng)江河口兩套三維數(shù)值模式。運(yùn)用實(shí)測(cè)資料對(duì)模式計(jì)算的水位、流速、流向、鹽度進(jìn)行驗(yàn)證,驗(yàn)證結(jié)果良好。 (3)利用庫(kù)內(nèi)水動(dòng)力三維數(shù)值模式探究庫(kù)內(nèi)的流場(chǎng)結(jié)構(gòu)和生成機(jī)制。模擬在恒定取水和供水流量情況下的吞吐流,冬、夏季不同盛行風(fēng)作用下的風(fēng)生流,以及吞吐流和風(fēng)生流共存下總流場(chǎng)。 模式計(jì)算結(jié)果表明：在穩(wěn)定狀態(tài)下吞吐流是由取水口和供水口流量的慣性驅(qū)動(dòng)產(chǎn)生的。在水庫(kù)的西區(qū)青草沙墾區(qū)南側(cè)的流速和流量大于北側(cè)的流速和流量。在水庫(kù)的中東區(qū),吞吐流主要沿南側(cè)向東流動(dòng),中部和北側(cè)流速很小。 在純風(fēng)應(yīng)力驅(qū)動(dòng)的情況下,風(fēng)應(yīng)力驅(qū)動(dòng)表層水體流動(dòng),水體向下風(fēng)向堆積,導(dǎo)致上風(fēng)向水位下降,下風(fēng)向水位上升,形成反向的水位梯度力,驅(qū)動(dòng)底層水體由下風(fēng)向向上風(fēng)向流動(dòng)。因此,表層水庫(kù)中的風(fēng)生流在表層和底層是反向的,底層實(shí)為補(bǔ)償流,流場(chǎng)結(jié)構(gòu)滿足流體運(yùn)動(dòng)的守恒性和連續(xù)性。 在吞吐流和風(fēng)生流共存情況下,總流場(chǎng)除了取水口附近水庫(kù)西北水域和供水口附近小范圍內(nèi)外,其它區(qū)域流場(chǎng)與僅由風(fēng)應(yīng)力產(chǎn)生的風(fēng)生流幾乎一致。這表明青草沙水庫(kù)的流場(chǎng)由風(fēng)生流控制,吞吐流量值相對(duì)較小。 (4)利用庫(kù)內(nèi)水動(dòng)力三維數(shù)值模式分析青草沙水庫(kù)的滯留時(shí)間。由于水庫(kù)的面積大,滯留時(shí)間存在空間上的差異性,本文將其劃分成6個(gè)區(qū)域來(lái)探討其水體滯留時(shí)間。針對(duì)不同的動(dòng)力狀況設(shè)計(jì)5組數(shù)值試驗(yàn),計(jì)算和分析水庫(kù)的滯留時(shí)間。 數(shù)值計(jì)算結(jié)果表明,在夏季一般情況下(東南風(fēng)5m/s,上閘兩潮進(jìn)水,下閘口兩潮排水,供水500萬(wàn)噸/天,自由水位),各區(qū)水體滯留時(shí)間存在較大差異,中南區(qū)最長(zhǎng)可達(dá)30天以上,西南區(qū)最短約為6.25天。整個(gè)水庫(kù)表層平均滯留時(shí)間約為25.21天,中層平均滯留時(shí)間約為25.21天,底層平均滯留時(shí)間約為25.33天。無(wú)風(fēng)有利于水庫(kù)的水體置換；東北風(fēng)相對(duì)于東南風(fēng)(夏季盛行風(fēng))更加不利于水庫(kù)的水體交換；在夏季盛行風(fēng)的條件下增加供水量,水體的滯留時(shí)間明顯縮短；低水位運(yùn)行,上游閘進(jìn)水時(shí)間、下游閘出水流量均減小,庫(kù)內(nèi)水動(dòng)力減弱,使得滯留時(shí)間變長(zhǎng),對(duì)水庫(kù)的水體置換不利。 (5)應(yīng)用改進(jìn)的長(zhǎng)江河口鹽水入侵三維數(shù)值模式,研究青草沙水庫(kù)取水口鹽水入侵來(lái)源。計(jì)算結(jié)果表明,在一般動(dòng)力條件下小潮后中潮、大潮、大潮后中潮和小潮期間北支倒灌占青草沙水庫(kù)取水口表層鹽水入侵比例分別為69.5%、89.3%、98.5%和99.5%,占底層鹽水入侵比例分別為34.9%、88.9%、98.5%和99.5%。除了小潮后中潮期間底層鹽水入侵來(lái)源主要來(lái)自下游外海(占65.1%),青草沙水庫(kù)取水口表層和底層鹽水入侵來(lái)源主要來(lái)自北支鹽水倒灌,尤其是大潮后中潮和小潮期間幾乎全部來(lái)自北支鹽水倒灌。
[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.

【學(xué)位授予單位】：華東師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TV697

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