發(fā)布時間：2018-04-29 16:55

  本文選題：鹽水入侵 + 數值模擬　； 參考：《浙江大學》2017年博士論文

【摘要】：錢塘江河口潮強流急,淤變化劇烈,是典型的強潮河口。該河口供應了杭州市80%的飲用水,是城市重要的水源地。多年來鹽水入侵嚴重影響取水口水質。研究錢塘江河口鹽水入侵對于保障城市飲用水安全具有十分重要的意義。論文依托國家科技重大專項課題-潮汐影響城市飲用水安全保障共性技術研究與示范(2009ZX07424-001)對錢塘江河口鹽水入侵及其影響因子展開系統(tǒng)研究。在錢塘江河口開展了多站同步潮位和鹽度實時觀測,據此分析了潮周期、半月潮、季節(jié)性及年際的鹽度時間變化。在潮周期和半月潮短歷時尺度上,鹽度變化取決于潮汐作用;在季節(jié)和年際的長歷時尺度上,鹽度變化則取決于徑流量。錢塘江河口鹽度的空間分布上,縱向上沿程遞減,最大梯度發(fā)生在倉前附近;垂線平均鹽度一般主槽低于邊灘,但變幅不大;鹽度垂向分層現(xiàn)象不明顯,分層系數多數小于0.3,表明錢塘江河口為強混合型。基于Savenije一維鹽度平衡方程,建立了錢塘江河口漲憩和落憩時刻鹽度的經驗解析模型,并對鹽度沿程空間分布及鹽水入侵距離進行了計算,結果與實測較為一致。提出一種改進粒子群算法優(yōu)化的小波神經網絡模型(IPSO-WNN),據此對錢塘江河口七堡鹽度時間序列進行了較好地模擬�；贔VCOM模式建立了錢塘江河口三維潮流鹽度數值模型,模擬的潮位、流速、流向和鹽度整體上與實測資料吻合良好,說明模型能有效反映錢塘江河口水動力及鹽水入侵過程。基于模擬結果分析了枯季強潮期錢塘江河口富春江電站-澉浦水域鹽度的時空變化。平面分布上,鹽水隨潮流周期性往復運動,大潮期鹽水入侵嚴重,0.45等鹽度線可上溯至閘口與聞堰之間;小潮期鹽水入侵程度減弱,0.45等鹽度線回落到倉前與七堡之間。鹽度垂向分布均勻,紊動混合較充分,無論大潮還是小潮,漲憩時刻鹽度分層現(xiàn)象較漲急及落潮期明顯。基于三維鹽度的一系列數值試驗,研究了徑流量、潮汐、風速、風向及海平面上升等動力因子單獨變化時對錢塘江河口鹽度分布和入侵距離的不同影響。徑流和潮差是鹽水入侵的兩個主要影響因素。河口鹽度及鹽水入侵距離隨著上游徑流量的增加而減小,隨著下游潮差的增加而增加。風對鹽水入侵的影響表現(xiàn)在,與漲潮流向一致或相近的風應力作用下,河口整體鹽度大潮期降低而小潮期則有所增加,與落潮流向一致或相近的風應力作用下恰好反之。海平面上升后,鹽水入侵加劇,上升幅度越大,作用越顯著。相對海平面分別上升0.3、0.6和1.0m,鹽水入侵距離大潮期分別增加了 1.1、2.2和6.0 km,小潮期則增加了 2.8、5.9和9.8 km�；跀的＝Y果,發(fā)現(xiàn)鹽水入侵距離與徑流量大小成負指數關系,與潮差大小呈指數關系。通過非線性多元回歸分析,建立了鹽水入侵相對距離的指數函數(exp×(L/L_0)與相對潮差(H/h)和徑流弗勞德數(qr/(?))的冪函數之間的正比關系。在澉浦枯季8.21 m最大實際潮差下,南星橋和珊瑚沙取水口在徑流量為50和300 m3/s時半月內連續(xù)最長超標時間分別為10.4-11.5和0.2～1.4d,當流量達到500m3/s以后,兩個取水口均不超標。在澉浦15d最大潮差8.52和6.79 m情況下,滿足南星橋和珊瑚沙取水要求的最小抗咸流量分別為410和250 m3/s。兩個取水口在最不利風向(東向)作用下,兩個取水口平均鹽度增值分別為0.18和0.15,連續(xù)最長超標時間增值分別為2.1d和1.9h。
[Abstract]:The Qian Tang River estuary is a typical strong tidal estuary. The tidal current is a typical strong tidal estuary. The estuary is 80% of the drinking water in the city of Hangzhou. It is an important source of water in the city. For years, salt water intrusion seriously affects the water quality of the water intake. It is of great significance to study the intrusion of salt water in the estuary of the Qian Tang river. A major project of family science and technology - the research and demonstration of the common technology of tidal impact on the safety and support of urban drinking water (2009ZX07424-001), a systematic study on the intrusion of brine and its influence factors in the Qian Tang River Estuary was systematically studied. The real-time observation of multi station synchronized tidal level and salinity was carried out in the Qian Tang River Estuary. The salinity change depends on the tidal effect on the tidal cycle and the short diachronic scale on the tidal cycle and the half moon tide, and the salinity change depends on the runoff on the long calendar scale of the season and the interannual. The spatial distribution of the salinity of the Qian Tang River Estuary decreases in longitudinal direction and the maximum degree occurs near the warehouse; the vertical average salinity is the main main trough. It is lower than edge beach, but the variation is not obvious; the vertical stratification phenomenon of salinity is not obvious, and the stratification coefficient is less than 0.3, which indicates that the Qian Tang River estuary is a strong mixture. Based on the one dimensional salt balance equation of Savenije, the empirical analytical model of the salinity of the rise and rest at the Qian Tang River estuary is established, and the spatial distribution of salinity along the salinity and the intrusion distance of salt water are carried out. The results are in agreement with the measured results. A wavelet neural network model (IPSO-WNN) is proposed to improve the seven Fort salt time sequence of the Qian Tang River Estuary. Based on the FVCOM model, the three-dimensional tidal salinity numerical model of the Qian Tang River estuary is set up, and the simulated tidal level, flow velocity, flow direction and salinity are simulated. On the whole, the model is in good agreement with the measured data, indicating that the model can effectively reflect the hydrodynamic force of Qian Tang River and the process of brine invasion. Based on the simulation results, the spatio-temporal variation of the salinity of the Qian Tang River Kawaguchi Fuharuko power station, Kawaguchi Fuharuko power station in the season of dry season and strong tide is analyzed. In the plane distribution, the brine has a weekly reciprocating movement with the tidal current, and the brine invasion is serious in the tide period, 0 The salinity lines, such as.45, can be traced back to the gate and the weirs; the salinity of the salinity line falls down to the front of the storehouse and between the seven fort. The salinity vertical distribution is uniform and the turbulent mixing is more fully, no matter the tide or the small tide, the salinity stratification phenomenon is more urgent and the ebb period is obvious. A series of numerical tests based on the three-dimensional salinity. The effects of the dynamic factors such as runoff, tide, wind speed, wind direction and sea level rise on the salinity distribution and invasion distance of the Qian Tang River estuary are studied. The runoff and tidal difference are the two main factors affecting the intrusion of salt water. The salinity and the intrusion distance of the estuaries decrease with the increase of the upstream flow, with the downward tide. The effect of wind on the intrusion of salt water shows that under the action of wind stress that is consistent or close to the tide flow direction, the whole salty tide period of the estuary decreases and the tidal period increases, and the wind stress is the same as the wind stress which is consistent with the tide flow direction. The more significant the relative sea level rises 0.3,0.6 and 1.0m respectively, the intrusion distance of salt water increases 1.1,2.2 and 6 km respectively, while the tide period increases 2.8,5.9 and 9.8 km. based on the numerical model results, and finds the negative exponential relationship between the saline intrusion distance and the size flow size, and the exponential relationship with the tidal range. The proportional relationship between the exponential function (Exp * (L/L_0) and relative tidal range (H/h) and the Froude number of runoff (qr/)) is established. Under the maximum actual tidal range of 8.21 m in the dry season, the longest continuous exceeding standard time of the South Star Bridge and the coral sand intake in the half month of the runoff of 50 and 300 m3/s, respectively, is 10.4-11.5 and 0.2 ~ 1.4d, when the flow rate reaches 500m3/s, the two water intake is not exceeding the standard. Under the condition of the maximum tidal difference 8.52 and 6.79 m, the minimum salt resistance of the South Star Bridge and the coral sand water intake is 410 and 250 m3/s., respectively, and two water intake at the most unfavorable wind direction (East), and the average salinity of two intake ports is 0.18 and 0.18, respectively. 0.15, the longest time of exceeding the standard is 2.1d and 1.9h. respectively.

【學位授予單位】：浙江大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：TU991

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