本文選題：彎曲河流 + 非均勻沙起動(dòng)　； 參考：《天津大學(xué)》2014年博士論文

【摘要】：本文以彎曲型河流為研究對(duì)象，基于韓其為的泥沙運(yùn)動(dòng)統(tǒng)計(jì)理論體系，結(jié)合模型試驗(yàn)的方法，研究了水流的結(jié)構(gòu)特性及泥沙輸移過(guò)程。 在充分考慮非均勻沙的起動(dòng)低輸沙率、暴露度以及彎道的水力結(jié)構(gòu)導(dǎo)致的水面橫比降、環(huán)流影響的基礎(chǔ)上，對(duì)斜坡、彎道凹岸邊壁上的泥沙建立了較清晰的物理圖形，并較全面分析了各種力的作用，采用滾動(dòng)平衡方式推導(dǎo)了斜坡、彎道凹岸邊壁上泥沙起動(dòng)流速公式，所得彎道凹岸邊壁上泥沙起動(dòng)流速公式適用于粗、細(xì)顆粒，，并且概括性高，可以簡(jiǎn)化為順直河流邊壁泥沙起動(dòng)，以及床面泥沙起動(dòng)。 基于韓其為的泥沙運(yùn)動(dòng)統(tǒng)計(jì)理論體系，將轉(zhuǎn)移概率作為理論基礎(chǔ)，充分考慮了紊流猝發(fā)對(duì)床面顆粒起懸周期的影響，對(duì)非均勻沙的參考面平衡濃度公式進(jìn)行了推導(dǎo)。 采用物理模型試驗(yàn)的方法，對(duì)理想彎道的水流運(yùn)動(dòng)規(guī)律進(jìn)行了研究。其中包括水流動(dòng)力軸線、縱向流速、橫向流速、垂向流速的垂線分布，環(huán)流強(qiáng)度及其環(huán)流結(jié)構(gòu)等試驗(yàn)數(shù)據(jù)的時(shí)均值分析；以及紊動(dòng)強(qiáng)度、雷諾切應(yīng)力、紊流猝發(fā)等試驗(yàn)數(shù)據(jù)的脈動(dòng)值分析。 采用自然模型試驗(yàn)的方法，在提前塑造好的初始順直河槽中進(jìn)行模型試驗(yàn)，通過(guò)改變流量、初始河寬、入射角等研究河流演變過(guò)程和形成機(jī)理，采用粒子跟蹤技術(shù)（PTV）來(lái)進(jìn)行流速測(cè)量。本文的四組試驗(yàn)比較好的反映了河流演變的過(guò)程，前三組研究河流成型以及從試驗(yàn)現(xiàn)象、試驗(yàn)后的地形、河流的平面形態(tài)等方面定性分析河流的演變過(guò)程，第四組試驗(yàn)主要研究彎曲河流的演變過(guò)程。試驗(yàn)成功塑造出順直河流、分汊河流、彎曲河流，在試驗(yàn)過(guò)程中出現(xiàn)了淺灘、邊灘、江心洲、裁彎取直等典型的試驗(yàn)現(xiàn)象。通過(guò)對(duì)試驗(yàn)結(jié)果分析得出江心洲形成過(guò)程、彎曲河流形成過(guò)程以及流量對(duì)于河型的影響等基本結(jié)論。
[Abstract]:In this paper, the structure characteristics and sediment transport process of river flow are studied based on the statistical theory system of sediment movement based on Hanqi River and the method of model test. On the basis of fully considering the effect of incipient low sediment transport rate, exposure degree and hydraulic structure of curved channel on water surface transverse ratio drop and circulation, a clear physical figure of sediment on slope and concave bank wall is established. The effect of various forces is comprehensively analyzed, and the formula of sediment starting velocity on slope and concave bank wall is derived by rolling balance method. The obtained formula is suitable for coarse, fine particles and high generality. It can be simplified as the sediment incipient on the side wall of the straight river and the sediment incipient on the bed surface. Based on the statistical theory system of sediment movement, the transfer probability is taken as the theoretical basis, and the influence of turbulent burst on the suspended period of bed surface particles is fully considered, and the equilibrium concentration formula of reference surface of non-uniform sediment is deduced. In this paper, the law of flow motion in ideal bend is studied by using physical model test method. It includes the time-mean analysis of the experimental data such as the axis of the flow power, the longitudinal velocity, the transverse velocity, the vertical velocity, the circulation intensity and the circulation structure, and the turbulence intensity, the Reynolds shear stress, etc. Analysis of pulsation value of turbulent burst and other test data. The natural model test method is used to study the evolution process and formation mechanism of the river by changing the flow rate, the initial river width, the incident angle, and so on. Particle tracking technique (PTV) is used to measure velocity. The four groups of experiments in this paper reflect the process of river evolution very well. The first three groups study river formation and qualitatively analyze the evolution process of river from the aspects of experimental phenomenon, topography after experiment, plane shape of river, etc. The fourth group mainly studies the evolution of curved rivers. The experiment successfully molded the straight river, the branching river flow and the curved river. During the test process, the typical experimental phenomena such as shoals, banks, Jiangxinzhou, cutting and bending straightening and so on were found. Through the analysis of the experimental results, the basic conclusions such as the formation process of Jiangxinzhou, the forming process of curved river and the influence of discharge on the river pattern are obtained.
【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：TV143

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本文編號(hào)：2009646