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  本文選題：彎曲河流 + 非均勻沙起動�。� 參考：《天津大學》2014年博士論文

【摘要】：本文以彎曲型河流為研究對象，基于韓其為的泥沙運動統(tǒng)計理論體系，結合模型試驗的方法，研究了水流的結構特性及泥沙輸移過程。 在充分考慮非均勻沙的起動低輸沙率、暴露度以及彎道的水力結構導致的水面橫比降、環(huán)流影響的基礎上，對斜坡、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，采用滾動平衡方式推導了斜坡、彎道凹岸邊壁上泥沙起動流速公式，所得彎道凹岸邊壁上泥沙起動流速公式適用于粗、細顆粒，，并且概括性高，可以簡化為順直河流邊壁泥沙起動，以及床面泥沙起動。 基于韓其為的泥沙運動統(tǒng)計理論體系，將轉移概率作為理論基礎，充分考慮了紊流猝發(fā)對床面顆粒起懸周期的影響，對非均勻沙的參考面平衡濃度公式進行了推導。 采用物理模型試驗的方法，對理想彎道的水流運動規(guī)律進行了研究。其中包括水流動力軸線、縱向流速、橫向流速、垂向流速的垂線分布，環(huán)流強度及其環(huán)流結構等試驗數(shù)據(jù)的時均值分析；以及紊動強度、雷諾切應力、紊流猝發(fā)等試驗數(shù)據(jù)的脈動值分析。 采用自然模型試驗的方法，在提前塑造好的初始順直河槽中進行模型試驗，通過改變流量、初始河寬、入射角等研究河流演變過程和形成機理，采用粒子跟蹤技術（PTV）來進行流速測量。本文的四組試驗比較好的反映了河流演變的過程，前三組研究河流成型以及從試驗現(xiàn)象、試驗后的地形、河流的平面形態(tài)等方面定性分析河流的演變過程，第四組試驗主要研究彎曲河流的演變過程。試驗成功塑造出順直河流、分汊河流、彎曲河流，在試驗過程中出現(xiàn)了淺灘、邊灘、江心洲、裁彎取直等典型的試驗現(xiàn)象。通過對試驗結果分析得出江心洲形成過程、彎曲河流形成過程以及流量對于河型的影響等基本結論。
[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.
【學位授予單位】：天津大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TV143

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本文編號：2009646