水电站进水口快速闸门水力学分析

主要分析水电站进水口快速闸门在动水关闭过程中流量、临界开度和闸门受水流作用力(闸顶水压力、闸底水压力和闸门水平压力)等问题。根据模型试验所观测的水力现象和非恒定流计算理沦,提出了计算电站闸门、引水管道的水力参数(流量、水头和通气孔水位等)的数学模型。实例计算结果和模型试验结果基本吻合。     

渠道非恒定流水力学响应研究

输水渠道中的水位将随流量的改变而产生波动,且由一种恒定流状态过渡到另一种恒定流状态需要经过一段稳定的时间。这一水力变化过程与渠道自身的结构特性、渠道运行方式的选择和流量变化的幅度、速率有关。通过对渠道中的非恒定流进行数值模拟,对不同情况下渠道的水力学响应进行了研究。     

南水北调中线输水调度实时控制策略

科学合理的输水控制策略是保障长距离调水工程安全平稳运行的基础,根据控制策略实现向各分水口门供水计划的目标。在总结现有输水调度控制研究成果基础上,通过结合调度运行实际,综合考虑目标水位控制的鲁棒性、水位降幅的约束性、渠道上下游水情的统筹性因素,对输水调度控制策略进行了改进,提出了基于流量变化、水位变幅相耦合的实时调度控制策略。根据流量变化对渠段进行水量平衡分析,实施宏观控制,同时根据水位及其变幅实施微观调控。模型应用于南水北调中线渠段水位调整典型工况,通过渠首至测试断面坟庄河节制闸之间,约1 100 km的输水调度,成功实现了坟庄河节制闸前运行水位按需求降低0.5 m的目标,此过程中保持了其他渠段运行平稳。而传统控制策略由于未统筹考虑上、下游水情和水位降幅限制,测试时出现坟庄河节制闸前水位骤降,而其下游水位骤增的不利情况。     

灌溉渠道水力自动控制闸门运行稳定问题分析

在灌溉渠道运行的过程中,常常需要结合渠道水位、流量等信息,并利用水力自动控制闸门实现渠道运行效率的控制,从而使水资源得到高效利用。基于这种认识,以某项引水明渠建设工程为例,对灌溉渠道水力自动控制闸门的运行稳定问题展开阐述分析,为实现节制分水闸的合理利用提供参考。     

受水电站泄流影响的水位流量关系分析及改正方法

一、水电站泄流与非恒定流1.水电站机组起动与停机都很迅速,因而其泄流过程变化很大,并导致尾水河道的水位、过水断面和流速等在瞬时内速变,这种水力要素随时间变化的河渠水流属明渠非恒定流。当水电站机组开机时,闸门突然开启,流量骤增,在尾水河道引起的波体,其传播方向与水流方向相同,且水位上升,这种波称为顺涨波;当水电站机组停机时,闸门突然关闭,     

水库防洪优化调度的恒定出流模型及应用

现行水库洪水优化调度数学模型存在泄流闸门开度不断调整及时段间流量突变的问题。针对这些问题,将水库防洪优化调度数学模型分为时段内出库流量线性变化的瞬时出流模型和时段内出流不变的恒定出流模型。对于1个水库和1个防洪控制点所组成的基本防洪系统,应用矩形入流条件的河道洪水演进方法,以时段内恒定的出库流量为决策变量,构建水库防洪优化补偿调度数学模型。实例计算结果表明:恒定出流模型比瞬时出流模型占用的防洪库容减小0.05%~0.18%、最大下泄流量有增有减,即恒定出流模型既不劣于瞬时出流模型,也能很好地解决瞬时出流模型存在的问题。同时,实例揭示的水库二次补偿调节比等蓄量调度方式减小防洪库容10.6%,为确定水库的防洪库容提供了新的方法。     

水文资料整编流量测验数据的检查

介绍了水文资料整编数据中的流量相关数据的检查情况。根据南方片整编程序推流数据文件中时间数据自动调取遥测水位数据文件中相应时间的水位数值,并与推流数据文件中的水位进行对比,检查水位数据正确性。特别是根据推流数据的开关闸时间和测流开始时间、结束时间来查找相应的遥测水位文件中的水位,并将查找出来的遥测水位与测流水位进行比较,水位不同的就列一个文件进行提示,并将推流过程和测流过程转换成DAT文件,展绘到水位过程线CAD图上以便对时间数据进行校核。同时对流量计算文件中的水位进行对比检查。     

长距离自流型渠道输水控制的二步法研究

提出了一种针对自流型渠道输水的最优化控制的两步法。第一步是控制各闸站流量使渠段水位(或蓄水量)达到目标水位(或蓄水量),第二步是调整流量使渠段水位稳定。建立了使渠道内水流在最短时间内恢复到正常运行水位的最优渠道输水控制模型。构建了长距离渠道输水控制的一系列约束条件,包括渠道下游需水量约束、最高控制水位、水位最大容许下降速度、渠道容许过流能力、最少的开机次数等。提出了利用线性规划或将大系统分解为若干子系统求解的方法。算例结果表明,用传统的渠道控制方法需要几天才能使水位恢复到目标水位的渠道,用本优化方法控制,可以在几小时内使渠道水位达到目标水位并达到稳定。     

渠道自动化控制系统及其运行设计

渠道运行控制系统可以根据渠道水位、流量等信息来提高渠道的运行效率,降低运行成本,提高水资源利用率。系统介绍了渠道运行方式和自动化控制的概念,扼要论述了近年来在长距离输水渠道运行方式和自动化控制方面的研究和相关成果,指出其中存在的问题和可能改进的途径。根据渠道运行控制系统多输入多输出、模型非线性、扰动随机性等特点,对控制解决方案进行了探讨,并在渠道运行方式选择、控制算法与闸门控制模式等方面指出了进一步的研究方向。     

闸下变动水位的船闸输水水力学计算

为解决强潮海域闸下潮位变化剧烈的船闸输水系统水力学计算问题,以现有规范为基础,从输水计算原理出发,推导了变动水位条件下的输水水力学计算方法,应用该方法计算分析了变动水位对三堡船闸安保工程输水的影响,并对闸室面积、初始水头、闸外落潮速度等因素进行敏感性计算分析。结果表明,采用该方法计算得到变动水位条件下输水时间缩短,最大流量、最大比能也小于取初始恒定水位的计算成果,结果更符合强潮海域船闸实际输水过程,为类似条件船闸输水水力学计算提供了一种技术、经济合理可行的计算方法。     

珠江三角洲感潮河网区水环境引水调控研究

本文以珠江三角洲中顺大围为例,提出通过引水调控措施将内河涌由双向流变为单向流改善河涌水环境,建立水量水质联合调控模型,模拟引水调控实施效果。调控结果表明,在截污的前提下,通过科学调度泵站及围内节制闸,从上游引入大量外江清水,抬高内河水位,加快水体循环,可逐步改善围内水环境;对类似河涌的水环境整治,可建立河涌与外江互通可控的水网体系,同时对内河涌的点源和面源污染采取截污治理措施,从根本上解决内河涌污染问题。本文的研究可为感潮河网区河涌整治提供参考,并为感潮河网区引调清水工程的实施提供借鉴。     

渭河拦河闸闸门选型及设计研究

闸门选型是拦河闸建设工作的重要组成部分,通过定量计算和综合分析,得到如下结论：①综合考虑渭河宝鸡市区段的地形、地质、河道特性以及施工管理等因素,建议选择开敞式平底拦河闸,并且采用平板闸门及固定式启闭方式。②设计拦河闸轴线全长626 m,闸底板高程579.9 m,设闸孔29处,闸孔宽度为19 m,属于大（1）型I等水利工程。     

Floodgate Operations and Fish Communities in Tidal Creeks of the Lower Fraser River (British Columbia,Canada)

Tidal creeks in large coastal deltas can be important habitat for fish but are often highly modified by human activities. Connectivity between tributary creeks and mainstem channels is often constrained by structures such as dikes and floodgates, designed to protect urban and agricultural areas from flooding. While they play important roles in flood mitigation, floodgates can diminish habitat quality and block fish from accessing tidal creeks. It is likely that floodgates differ in their operations and may consequently open for different amounts of time; however, floodgate operations and their effects are not well quantified. We asked the question: how does the mechanical functioning of these floodgates affect fish communities in tidal creeks? We used time-lapse cameras and quantified the timing of gate openings for 22 tributaries of the Lower Fraser River in British Columbia, Canada, and related these operational data to differences in fish communities above and below floodgates. Floodgate operations varied substantially, with some floodgates opening daily while others opened less than 20% of the day, on average. Sites with floodgates that seldom opened were associated with greater differences in fish communities and with reduced upstream native species richness by about one species on average. Where floodgates opened infrequently, we also found lower upstream dissolved oxygen concentrations than at sites where floodgates opened for longer periods of time. Thus, floodgate operations can influence fish communities as well as water quality. These data indicate a large scope for improving floodgate operations for connectivity.     

Flow and sediment dynamics in a low sinuosity, braided river: Calamus River, Nebraska Sandhills

The interaction between channel geometry, flow, sediment transport and deposition associated with a midstream island was studied in a braided to meandering reach of the Calamus River, Nebraska Sandhills. Hydraulic and sediment transport measurements were made over a large discharge range using equipment operated from catwalk bridges. The relatively low sinuosity channel on the right-hand side of the island carries over 70% of the water discharge at high flow stages and 50–60% at low flow stages. As a result, mean velocity, depth, bed shear stress and sediment transport rate tend to be greater here than in the more strongly curved left-hand channel. The loci of maximum flow velocity, depth and bed shear stress are near the centre of the channel upstream of the island, but then split and move towards the outer banks of both channels downstream. Variations in these loci depend on the flow stage. Topographically induced across-stream flows are generally stronger than the weak, curvature-induced secondary circulations. Water surface topography is controlled mainly by centrifugal accelerations and local changes in downstream flow velocity. The averaged water surface slope of the study reach varies very little with discharge, having values between 0·00075 and 0·00090. As bed shear stress generally varies in a similar way to mean velocity, friction coefficients vary little, normally being in the range 0·07–0·13. These values are similar to those in straight channels with sandy dune-covered beds. Bedload is moved mainly as dunes at all flow stages. Grain size is mainly medium sand with coarse sand moved in thalwegs adjacent to the cut banks, and with fine sand at the downstream end of the island. These patterns of flow velocity, depth, water surface topography, bed shear stress, bedload transport rate and mean grain size can be accurately predicted using theoretical models of flow, bed topography and sediment transport rate in single river bends, applied separately to the left and right channels. During high flow stages deposition occurs persistently near the downstream end of the island, and cut banks are eroded. Otherwise, erosion and deposition occurs only locally within the channel as discharge varies. Abandonment and filling of a strongly curved channel segment may occur by migration of an upstream bar into the channel entrance at a high flow stage.     

水库异重流一维水沙耦合模型

建立了基于库区不规则断面的一维非恒定异重流数学模型,并采用明流与异重流水沙输移模型交替运算的两步模式,即用潜入条件动态判别异重流计算的上游边界位置,将潜入点上游的明流浑水段与下游异重流段计算连接起来。水流运动、泥沙输移与河床变形过程完全耦合,采用TVD(Total Variation Diminishing)形式的MUSCL-Hancock格式进行数值求解。将该模型应用于恒定流量与释放定量悬沙两种条件下的异重流水槽实验模拟,比较了有无水面梯度项对模拟精度的影响,计算结果表明该模型能较为准确地预测异重流的厚度、含沙量分布及传播过程。     

香港九龙大坑东地下蓄水方案数值研究

香港九龙大坑东地下蓄水方案(Tai Hang Tung Storage Scheme-THTSS)是香港西九龙渠道改善二期计划的一个重要组成部分,其目标是解决香港九龙繁华拥挤、人口稠密的商业中心旺角一带的洪水淹没问题。THTSS即是在经常洪水淹没区域(大坑东和界限街水渠交接处)上游足球场下面建立一个100 000 m3的地下蓄水池。本文建立了一个能处理明渠缓流和急流、封闭管道有压流、侧流堰和渠道汇合处过渡流于一体的一维水力数学模型,用1:22正态物理模型恒定流下的结果进行验证。数值模型计算了在50年一遇暴雨下,非恒定洪水在不同的侧流堰方案下的流动过程。结合物理模型试验结果,选择最佳的地下蓄水方案。计算结果表明,大坑东地下蓄水方案确实能加强旺角地区地洪水控制能力,并能通过50年一遇暴雨的洪水。     

Impact of rainstorm-triggered landslides on high turbidity in a mountain reservoir

Typhoon-triggered landslides deliver huge amounts of sediment to the upstream channel of the Shihmen Reservoir in northern Taiwan. Observation data regarding landsliding, sediment discharge and water turbidity following five major typhoon events from 1985 to 2006 demonstrated that each time water turbidity in the reservoir area rapidly increased up to ten-fold from the river catchment drainage, and the weight of landslide debris exceeded total sediment discharge five-fold. The fact that huge amounts of landslide debris still remained on upstream slopes and water turbidity suddenly increased in the reservoir area but not in upstream channel implied that the increasing water turbidity in the Shihmen Reservoir was indirectly related to the large landslides occurring in the upstream catchment. The main cause of high turbidity in the reservoir area was that, during a typhoon event, high water discharge flowing into the reservoir scoured the fine fraction sediment at the bottom of the reservoir and formed hyperpycanl flow with high turbidity, which then ascended to contaminate the reservoir surface water.     

Water renewal estimates for aquaculture developments in the Richibucto estuary,Canada

Water renewal in semi-enclosed coastal areas is crucial for the supply of oxygen and seston and for the removal of organic loadings from finfish or shellfish aquaculture sites. Water renewal depends on hydrodynamic processes and can have a complex spatial distribution due to irregular topographic features. This study describes some physical oceanography observations gathered in the Richibucto estuary, New Brunswick, Canada, and provides an estimate of the spatial distribution of water renewal in the North Arm, a location in the estuary where the largest American oyster (Crassostrea virginica) aquaculture operation in eastern Canada is located. The estuary changes from a well mixed estuary to a partially stratified estuary depending on runoff conditions. Tides are mixed but mainly diurnal due to the nearby presence of the second M₂ amphidromic point in the Gulf of St. Lawrence. Tidal amplitudes vary from 0.3 to 0.6 m and show a slight increase some 35 km upstream. Currents in the main channel can reach over 0.60 m s⁻¹ during ebb and 0.3 m s⁻¹ during flood, with a slack water period of approximately 8 h. Low frequency sea level fluctuations have a range of 0.5 m at the mouth and are coherent within the estuary. Hydrodynamic and advection-dispersion models are used to calculate the spatial distribution of the local renewal time (LRT) in the North Arm for high and low freshwater discharge conditions, using the dissolved tracer method. Results show that the LRT varies from less than 5 d at the downstream end of the North Arm to over 100 d further upstream. When averaged over the entire North Arm, the integral renewal time (IRT) is estimated to vary only from 8 to 21 d depending on the season. The LRT and IRT estimates are major improvements over conventional renewal estimates using tidal prism methods.