粗化床面非均匀沙推移质运动扩散特性研究

对泥沙颗粒运动规律的把握是准确估算推移质输沙率的基础.本文开展了粗化床面条件下的水槽试验,分析了非均匀沙颗粒的均方位移和速度自相关系数变化,并与已有均匀沙试验进行了对比.结果表明,粗化床面存在着由单个或多个粗颗粒组成的粗化结构体,形成比平整床面更复杂的底部边界,粗化结构体对泥沙颗粒运动造成较大影响,颗粒在运动过程中与水...     

Experiments and numerical simulations on transport of dissolved pollutants around spur dike

The flow field around a spur dike has three-dimensional characteristics.In order to analyze the influence of the flow field on pollutant transport,based on a compressive volume of fluid(VOF)scheme,the three-dimensional transient compressive pollutant transport model(CPTM)and the cubic equation(CE)bounded differencing scheme were developed.For the calibration and validation of CPTM,laboratory experiments were carried out in a flume with a non-submerged spur dike.The spur dike was angled at 60°,90°,and 120° from the upstream direction.The simulation results agreed with the experimental results.The simulations and experiments showed that the distribution of pollutant concentration was determined by circumfluence and the main flow.Concentration decay in the circumfluence zone was slower than that in the main flow.Downstream of the spur dike,the concentration fluctuation became intensive with the increase of spur dike angle.     

基于降雨-径流试验的高寒草甸产流机制研究

对黄河源区高寒草甸产流机制进行研究,为河源区生态环境保护、水资源科学规划管理提供基础水文理论认知。基于野外降雨-径流试验,通过回归分析构建考虑坡度和覆被因子的暴雨和中小雨产流计算模式,精度良好,能够反映暴雨和中小雨2种降雨模式下高寒草甸产流的一般特征。试验结果表明,因草甸土-植体系蓄容能力较强,高寒草甸区地表产流主要发生在暴雨模式下,中小雨模式下的地表产流量一般很小。模式应用表明,草甸发生退化后,暴雨和中小雨入渗均有减少,暴雨模式下退化草甸比高覆草甸入渗减少约12%,中小雨模式下减少约3%。     

模型桥墩局部冲刷瞬时地形数据自动获取装备研制

模型试验中冲刷地形测绘装备相对落后,致使桥墩周围局部冲刷瞬时地形数据无法实时获取,冲刷动态发展过程及机理的模型试验研究工作难以开展。研制了一种模型桥墩局部冲刷瞬时地形数据等值线自动绘制装备,并利用室内水工模型试验优化了各组成的性能指标,量化了绘制装备的设计参数,分析了监测系统在模型应用中的测绘精度及在工程原型中的适用性。模型试验研究表明,该装备结构简单,操作方便,加工制作成本较低,精度及灵敏性较高,能够快速获取动态过程中局部冲刷瞬时地形等值线,适用于局部冲刷发展影响流场特性研究中的水下地形快速测绘,也可按放大比尺制作成型后应用于涉水建筑物周围水下地形监测。     

压力抑制条件下生烃定量模拟实验研究——以渤海湾盆地济阳坳陷为例

烃源岩生烃过程受温度、压力等地质条件的影响,这一过程可以通过化学动力学方法来描述。通过2种模拟实验方法,即开放体系和封闭体系,研究了渤海湾盆地济阳坳陷不同沉积环境的4套主力烃源岩的生烃动力学特征。封闭体系模拟实验中设计了与地下相同的垂向等效压力条件。通过对比分析认为,压力对烃源岩的生烃过程具有不同程度的抑制作用,主要表现在对不同类型的烃源岩及在不同的演化阶段其影响均有所不同;随母质生烃潜力的增大,以及在演化程度增大、地层压力增高的情况下,生烃抑制作用越明显。根据实验结果,确定了4套烃源岩各演化阶段有压力条件存在的生烃动力学参数。     

基于BIM+GIS的大坝安全监测信息可视化展示技术研究

为了解决传统大坝监测信息三维可视化程度低,展示不够直观、形象等问题,采用BIM+GIS技术,将监测信息展示从传统二维空间拓展到三维空间.对BIM建模、模型轻量化、三维可视化展示以及系统功能设计进行了研究,通过在桃源水电站的应用实例表明,BIM+GIS技术能够实现大坝安全监测信息三维可视化展示,展示效果更为形象、生动,具...     

堰塞坝溃决模拟研究综述与展望

堰塞坝几何形态、粒径级配和库容决定了其溃决机理的复杂性,而溃决过程的精细模拟和峰值流量的准确预测是应急处置的基础和关键.堰塞坝溃决过程与模拟技术是面向国家防灾减灾重大需求的前沿热点问题.在系统梳理国内外试验和数值模拟研究进展的基础上,指出以往试验研究坝体尺度小,足够大的库容基本未模拟,难以显示最终溃口形态;数学模型假设...     

不同植被类型对堆积体坡面径流特性的影响

针对植被防护堆积体侵蚀动力机制的问题,通过野外模拟降雨试验,分析直根系和须根系植被对堆积体径流流速、水力和水动力参数的影响.结果表明:植被削减堆积体平均侵蚀速率达88.34％～92.88％,直根系消减平均流速效益为50.51％,须根系为21.32％～35.61％;裸坡和植被堆积体径流流型均属于层流(雷诺数<40),裸坡...     

Simultaneous visualization of flow field and evaluation of local heat transfer by transitional impinging jets

A combined approach has been employed to characterize the flow field and local heat transfer in jet impingement configurations, featuring a mass transfer experiment and a digital visualization technique. A jet velocity range is spanned to ensure flow regime transition.The well-known heat/mass transfer analogy has been used to infer on the local heat exchange on a infinite plate. In this experiment, a naphthalene film is ablated from a disk, due to jet exposure. Automated contact measurements of the variation of film depth in the stagnation region and beyond have been performed. From the local naphthalene loss rate the local heat transfer is then inferred. Coherent structures are created both at the interface between free jet and quiescent medium and upon impingement at plate, and need to be visualized in the vicinity of stagnation. To this end a particle image velocimetry system is exploited to extract the two components velocity instantaneous information.Ablation measurements confirm the non-monotonic progress of local heat transfer for small nozzle-to-plate spacings. The visualizations evidence that local heat transfer is strongly influenced by impingement structures: the maximum heat transfer coefficient offset which can be detected is due, even for laminar or transitional jet, to large-scale toroidal vortices impacting on the plate.