【作者】 檀会春；

【导师】 张华庆； 赵利平；

【作者基本信息】 长沙理工大学 ， 港口、海岸及近海工程， 2010， 硕士

【摘要】 天然河流几乎都是弯曲的,弯道可以看成是组成河流的最基本的单元,由于边界条件的不同,弯道中行进的水流运动特性也与顺直河段中不同。弯道特有的几何特征和边界条件,弯道水流运动呈螺旋流运动,弯道环流的出现,引起弯道泥沙的横向输移,形成弯道凹岸冲刷、凸岸淤积的冲淤特性。弯道水流的研究成果在许多工程领域中,如河流治理、航道整治、引水防沙、桥墩防护等,都得到了广泛的应用。由于弯道水流特有的螺旋流,以及其本身特殊的几何特征和边界条件,使得这种水流具有复杂的三维特性,因此研究弯道水流的三维特性是十分有意义的。本文试从物理模型试验与数值模拟两种方法共同分析弯道水流的三维水力特性,较为综合的分析了180°弯道水流的三维特性,并通过建立数学模型对物理模型进行验证和补充。本文主要研究内容包括：本文首先总结了前人有关弯道水流水面比降、流速分布及环流等结论,以及弯道水流数学模型的发展现状。本文建立了180°矩形弯道水槽,在试验中通过运用小威龙三维流速测量了多个断面和测点的三维流速,分析在不同工况下水槽中各测点三维流速的分布规律、各横截面流速场、纵断面流速场、沿水深方向的流速场、弯道环流强度及分布、弯道水流紊流强度及阻力特性等水力特性。此外,本文建立三维RNGκ-ε紊流数学模型,通过对180°弯道水槽中0°、90°、180°三个典型断面流速场情况的验证,进而分析了物理模型由于仪器限制而未能测量分析的表面流速场、近表层流速场、自由水面形态、紊动动能和紊动强度分布等,建立的三维数学模型可以应用于三维水流的计算,并且对物理模型试验进行验证和补充。本文通过物理模型和数值模拟较为系统的分析了180°弯道水流的水力特性,得出了一系列相关的结论,建立的数学模型可以应用于其它水流三维试验研究,本文可以为今后弯道水流的三维特性研究提供了试验依据和理论依据。更多还原

【Abstract】 Almost all. of the natural river bend,curve can be seen as the basic component of the composition of the river, because of different boundary conditions,curve make the flow characteristics are different with straight reach.Curve have specific geometry and boundary conditions,bend flow are spiral flow movement,circulation corner are appeared,horizontal transport of sediment caused by bend,formation curve concave bank,convex bank erosion and deposition characteristics deposition. Bend flow of research results are used in many engineering fields,such as river treatment,channel improvement, water sediment prevention,protection,and piers have been widely used.As the bend flow have characteristic curve,and have their own specific geometry and boundary conditions makes this flow have a complex three-dimensional characteristics of flow. Therefore,the study of three-dimension-al bend flow features is very significant.This paper from the physical model test and numerical simulation methods of joint analysis of two three-dimensional curved hydraulic characteristics of flow, it more comprehensive analyse 180°bend three-dimensional characteristics of flow, and through a mathematical model to verify the physical model and complement. This paper studies include:this paper summarizes the previous water surface slope of the curve,velocity distribution and circulation,etc.,and the development of mathematical model of bend flow status.In this paper, a 180°rectangular corner sink, in the experiment by using three-dimensional velocity measurement of VECTRINO several sections and three-dimensional velocity measurement points.Analysing each tank three-dimensional velocity measurement points distribution in different conditions.The cross-sectional velocity field,longitudinal velocity field,along the depth direction of the velocity field, circulation intensity and distribution of bend, bend strength and resistance characteristics of turbulent flow and other hydraulic characteristics.In addition,this paper three-dimensional RNG turbulence model,through u-turn on the sink in the 0°,90°,180°three typical cases of verification of velocity field, because of further analysis of the physical model is limited because instruments can not measure the surface velocity field analysis,near surface velocity field,Free surface shape,turbulent kinetic energy and turbulent intensity distribution, the establishment of three-dimensional mathematical model can be applied to the calculation of three-dimensional flow, and Verify and add the physical model test.In this paper, physical models and numerical simulation of the more systematic analysis of the 180°corner flow of the hydraulic characteristics,and obtain a series of relevant conclusions, the mathematical model can be applied to other three-dimensional test of flow, and this paper provides an experimental basis and theoretical basis for the future study three-dimensional characteristics of flow.更多还原