本文選題：彎道水流 + 環(huán)流　； 參考：《天津大學(xué)》2014年碩士論文

【摘要】：水資源與人類生活各個(gè)領(lǐng)域緊密相關(guān),近年來,在許多水力學(xué)領(lǐng)域取得了豐碩成果,但我們對(duì)彎道水流的三維水流結(jié)構(gòu)、紊動(dòng)特性、河流床面形態(tài)及演變的認(rèn)識(shí)仍有待進(jìn)一步深入,這使得在預(yù)測(cè)河床演變、應(yīng)對(duì)突發(fā)情況等方面面臨著一定的困難。由此可見,針對(duì)天然彎道中水流的水動(dòng)力特性以及河床地貌形態(tài)演變的研究十分必要。由于實(shí)測(cè)資料的獲取較為困難且存在費(fèi)用昂貴、精度較差的問題,我們將在室內(nèi)明渠彎道水槽中開展研究。本實(shí)驗(yàn)設(shè)計(jì)了一個(gè)由一個(gè)180o彎段和兩個(gè)直段組合而成的常曲率彎道水槽模型,運(yùn)用聲學(xué)多普勒測(cè)速儀對(duì)模型中水流進(jìn)行精細(xì)測(cè)量,并獲取到每個(gè)測(cè)點(diǎn)三個(gè)不同方向的瞬時(shí)速度,以此為基礎(chǔ)展開分析。本文分析了水流流向平均流速及其速度等值線圖、水動(dòng)力軸線,沿垂線分布的三個(gè)方向的流速及彎道環(huán)流,并得到了在單彎道中水流結(jié)構(gòu)特點(diǎn),為天然河流連續(xù)彎道的研究打下了基礎(chǔ)。彎道水流運(yùn)動(dòng)以及泥沙輸移將引起河流床面形態(tài)的改變,這對(duì)河流演變具有重要影響。根據(jù)水流阻力規(guī)律,對(duì)床面形態(tài)進(jìn)行預(yù)測(cè)是河流動(dòng)力學(xué)中研究的一個(gè)重要研究方面。河流在流動(dòng)過程中存在水流阻力損失,而水流阻力損失則隨著來水來沙條件和床面形態(tài)的改變而改變。水流阻力規(guī)律既決定于床面形態(tài),同時(shí)也能反映床面形態(tài)特征。基于河流阻力規(guī)律這一理念,本文結(jié)合水槽試驗(yàn)研究成果,根據(jù)水流阻力規(guī)律表達(dá)形式,對(duì)不同床面形態(tài)進(jìn)行了區(qū)分,給出兩個(gè)決定床面形態(tài)的無量綱參數(shù),繪制了不同床面形態(tài)的劃分圖,論述了床面形態(tài)變化與床面形態(tài)參數(shù)之間的關(guān)系,得到了床面高、低能態(tài)的分界線方程以及不同床面形態(tài)間的分界線方程,確定了不同階段的床面形態(tài)判別標(biāo)準(zhǔn)表達(dá)范圍。
[Abstract]:Water resources are closely related to every field of human life. In recent years, great achievements have been made in many fields of hydraulics. The understanding of the shape and evolution of river bed surface needs to be further deepened, which makes it difficult to predict the river bed evolution and to deal with unexpected situations. Therefore, it is necessary to study the hydrodynamic characteristics of water flow in natural bends and the evolution of river bed geomorphology. Due to the difficulty of obtaining the measured data and the problems of high cost and poor precision, we will carry out the research in the indoor open channel bend flume. In this experiment, a constant curvature bend flume model composed of a 180 o bend and two straight sections is designed. The acoustic Doppler velocimeter is used to measure the water flow in the model, and the instantaneous velocities in three different directions of each measuring point are obtained. On this basis, the analysis is carried out. In this paper, the average flow velocity and its velocity isoline map, hydrodynamic axis, flow velocity and curved circulation in three directions along the vertical line are analyzed, and the characteristics of the flow structure in a single bend are obtained. It lays a foundation for the study of continuous bend of natural rivers. The flow movement and sediment transport in curved channel will cause the change of river bed shape, which has an important influence on river evolution. According to the law of flow resistance, prediction of bed shape is an important research aspect in river dynamics. In the course of flow, the flow resistance loss of the river changes with the change of the condition of incoming water and sediment and the shape of bed surface. The flow resistance law is not only determined by the bed shape, but also can reflect the bed surface characteristics. Based on the concept of river resistance law, combined with the research results of flume test, according to the expression form of flow resistance law, different bed surface forms are distinguished, and two dimensionless parameters determining bed surface shape are given. The partition diagram of different bed surface morphology is drawn, and the relation between bed shape change and bed surface shape parameter is discussed. The boundary equation of bed surface high and low energy state and the boundary line equation between different bed surface morphology are obtained. The standard expression range of bed surface morphology at different stages was determined.
【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TV147

【參考文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前3條

1 唐仁杰;連續(xù)兩彎明渠水流特性水槽試驗(yàn)研究[D];長(zhǎng)沙理工大學(xué);2009年

2 王博;連續(xù)彎道水流及床面變形的試驗(yàn)研究[D];清華大學(xué);2008年

3 許棟;明渠沙紋演化及其湍流動(dòng)力特性實(shí)驗(yàn)研究[D];天津大學(xué);2005年

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本文編號(hào)：1952526