THEORY AND NUMERICAL ANALYSIS OF THE INTERACTION BETWEEN TURBULENCE AND SUSPENDED SEDIMENTs

The coupled hydrodynamical-ecological model for Regional and Shelf Seas Coherens was modified through introducing sediment model in order to simulate suspended sediment transport and account for the interaction between turbulence and sediment. To discuss the effects of sediment on vertical eddy viscosity and diffusion coefficients, the damping function of sediment on turbulence was introduced into one equation k-ε turbulence closure model. Moreover, it is assumed that local equilibrium among turbulence production, dissipation and buoyancy destruction exist near the bottom. The local equilibrium assumption is introduced into the one equation k-ε model and the specific formulation of local equilihrium for one equation k-ε was derived. The tidal current was calculated for Youngkwang Bay near the west coast of Korea. Meanwhile, the suspended sediment was also simulated with the local equilibrium assumption and damping function of sediment on turbulence. It is found that the damping function of sediment reduces vertical eddy viscosity and diffusion coefficients. The local equilibrium assumption changes obviously bottom layer turhulence intensity and sediment concentration.     

黄土之父刘东生

地理学界有这样的说法：目前人类了解地球的自然历史有三本书，一本是深海沉积物，一本是极地冰芯，第三本便是中国的黄土。国际上认为，把黄土这本书念得最好的是中国的刘东生。     

沉积物中有机质检测方法差异研究

为对水系沉积物中有机质检测方法的选取提供依据,该文介绍了用重铬酸钾氧化法、灼烧减量法2种检测方法进行的对照检测,经分析,两种检测方法的检测结果相差1.8倍到7.3倍,差异显著,因此在水系沉积物评价时,应据不同的目的采用不同的方法,两者不能混用.     

MECHANISM AND PREDICTION OF MATERIAL ABRASION IN HIGH-VELOCITY SEDIMENT-LADEN FLOW

1. INTRODUCTION There are many heavily sediment-laden rivers in China, where the silt abrasion of hydraulic projects caused by high-velocity sediment-laden flow is severe. Prediction of the silt abrasion damage at the concrete surface in heavily sediment-laden rivers is one of the important problems to be solved in water conservancy and hydropower engineering. It is necessary to study the mechanism and prediction of material abrasion. In recent years, many researchers have focused their a…     

城市合流排水管道水-沉积物界面污染研究进展

城市合流排水管道中水-沉积物界面物质在雨水径流的冲刷作用下会将其中的污染物重新释放排入受纳水体,成为水体面源污染的重要来源。综述国内外对水-沉积物界面物质的组成、污染特性及模型模拟方面的研究进展。将水-沉积物界面污染物分成有机层、近床固体层和流动泥沙层，其中有机层和近床固体层有较高的有机物含量和含水量,流动泥沙层含有较多的挥发性物质。研究表明：水-沉积物界面物质抗侵蚀性微弱,含水量是影响其剪应力的最重要因素；已有水-沉积物界面的模型模拟研究主要集中在利用模型预测近床固体对初期冲刷的污染贡献、有机层的污染物侵蚀量和近床固体层的生物降解量等。认为今后应加强对水-沉积物界面污染特性的研究，建立适合本地的水-沉积物界面污染贡献模型。     

广州市排水管道沉积现状研究分析

对广州市典型区域排水管道沉积现状进行调研,分析了坡度、管径、管材、汇水区域性质、排水体制等因素对管道沉积的影响。调查显示,研究区域内一半的排水管道都存在不同程度的沉积现象,分析表明:坡度对管道沉积的影响最大,管道沉积量和管径成正相关;钢筋混凝土管道比PVC管道沉积现象严重;不同汇水区域中,老式小区、商业区管道沉积现象最严重;此外,分流制雨水管道比合流制系统沉积更甚。     

水库中沉积物与降雨和碳积累的关系及其对农田土地的影响

文章探究广西水库的沉积物中碳的积累及其与开发种植历史、降雨状态的关系。水库沉积物是由沉积在主要入口附近的粗糙沉积物与深水环境中积累的沉积物组成。对沉积物进行总碳和有机碳分析发现,浅水区的总碳变化比深水区明显,说明沉积物的积累与降雨呈线性关系。沉积物的清理被回用于周边的农田土地及新耕地的开垦,但沉积物的利用对农田土地存在的利弊影响有待进一步研究。     

内波形成与沉积作用

随着油气勘探向半深海、深海进发,地质工作对于半深海、深海沉积要求越来越高。20世纪50年代初兴起的浊流理论改变了对深水沉积的认识,并在一定程度上指导了深水油气的勘探。随着勘探手段的发展和地质认识的深入,不仅对浊流理论本身,特别是鲍马序列产生了新的认识,而且发现了大型深海沉积物波这种难以用现有的浊流理论、等深流理论解释的地质现象。内波理论的发展为解释这一地质现象提供了契机,也为深海砂体的预测提供了新的理论指导。     

城市河道环保疏浚的试验研究

在天津大沽排污河综合治理之前，在外环线9号桥至10号桥之间选取一段约100m长的河道作为试验段，对几种疏浚方案进行生产性试验，用以对整条大沽河的疏浚进行指导．试验研究的内容包括：沉积物的开挖、运输、脱水．试验中的2种清淤方法为：水力清淤和机械清淤；3种运输方式为：卡车、罐车和管道运输；3种脱水方法为：~风干、机械脱水和抽真空脱水．工程实施过程对环境的影响符合环保的要求．最后，对2种清淤方法、3种脱水方法和3种运输方法的组合，综合造价、对环境的影响、实施速度等因素进行了组合排序。     

LOCAL SCOUR AROUND A LARGE-SCALE VERTICAL CIRCULAR CYLINDER DUE TO COMBINED WAVE-CURRENT ACTION

The local scour around a large scale vertical circular cylinder due to combined wave-current action was experimentally and numerically studied in the present paper. Experiments were carried out to research the affect of the wave height, current velocity and the diameter of the cylinder on the scour process. The topography near the cylinder in various cases during scour was measured. The cylinder diameter affects the distribution of scour and deposition area. The maximum scour depth increases evidently when the current velocity increases, The maximum scour depth does not increase after the wave height retains a certain value. A numerical model using a finite element method for simulating the scour process was established. And the numerical results agree well with the measured data. The numerical model is more applicable in the case of large-scale cylinders.