临淮岗枢纽新建深孔闸水力计算

本文根据试验资料，对临淮岗枢纽工程深孔闸的水力计算进行了探讨，给出了各种流态的水力计算公式及流态判别条件，并绘制出闸堰流态分区模式图。     

闸站合建枢纽进水流态的特性研究

闸站合建枢纽容易引起枢纽上下游水流流态的特殊化和复杂化,水流紊乱对水力机组的运行将产生极为不利的影响,影响枢纽高效运行。结合工程实例,阐述两种改善枢纽进水流态的措施,并对优化前后的水流流态进行比较,证明了改进方案的优越性。     

引硫济金枢纽工程引水防沙及下游消能防冲模型试验的研究

通过模型试验，对甘肃省金昌市引硫济金枢纽工程的泄洪冲沙闸和溢流坝下游消能防冲效果，引水防沙效果及引水隧洞进口段水流流态进行了试验和研究。并以此为依据，为设计部门提供了合理的意见和建议；在此基础上，通过对枢纽工程运作后期进水闸水流，泥沙的运动特性进行分析和研究，运用“分离流区，束水攻沙”的原理解决了引硫济金枢纽工程的引水防沙问题。     

天桥水电站底面流混合消能及枢纽运行方案研究

通过水工模型试验，对天桥水电站除险加固工程底面流混合消能涉及到的分流比、下游流态和流速的变化以及枢纽运行方案作了有益的探讨。新增泄水建筑物，不仅可减轻双层泄洪闸的泄流压力，抬高下游尾水，改善下游流态，减轻下游冲刷，而且为新运行方案的实施创造了条件。同时，结合不同泄水建筑物的特点，总结出较为可行的洪水期多种流量下的运行方案，供工程运行参考。     

戍浦江河口大闸水力计算

根据试验资料,对戍浦江河口大闸枢纽工程挡潮闸的水力计算进行了探讨,给出各种流态的水力计算公式及流态判别条件,并绘制出闸堰流态分区模式图,为闸门的智能管理打下了水力学基础.     

茶子岗电站的枢纽布置与下游消能

茶子岗电站工程设计通过水工模型试验，解决了工程的枢纽布置和建筑物之间连接问题。对在在坝下游水深较浅的情况下，如何能形成面流消能流态提出了具体措施和办法。     

小资料

该模型是我国目前最大的比尺模型之一。从1973年起,用这一模型先后为工程枢纽布置方案、建筑物消能防冲、航道流速流态、电站导漂排漂及枢纽运用方案等科研项目进行了试验研究,为工程设计提供了依据。在解决航通流速流态的试验中,采用了比尺遥控     

低水头河床式水利枢纽总体布置中值得关注的问题

低水头河床式水利枢纽工程总体布置中涉及坝址位置、河道流态、合适的河段宽度、泄洪闸净宽、闸底槛高程、枢纽总体布置等关键问题，通过一些工程实例分析，总结了上述问题在设计中处理的一般性规律。     

柳城水电站工程枢纽优化布置试验研究

柳城水电站工程原枢纽布置的水工模型试验结果表明,受上、下游河床高程及侧收缩的影响,水闸的泄流能力不足,同时,电站进口的流态较差,尾水出流直冲船闸下游引航道口门区,严重影响通航安全;试验中通过对枢纽附近河床的开挖、在船闸上游引航道左侧滩地修筑导流堤以及将电站与水闸之间的导流墙由实体墙改为空心透水墙.提高了泄流能力,改善了电站进口水流流态及船闸下游引航道的通航条件.     

高坝泄槽隔墙静动力稳定分析

国内某混凝土重力坝采用了与传统方式不同的高低坎多孔淹没射流消能方式。为宣泄各级流 量洪水与调整枢纽水流流态，在溢流坝段中间设置了隔墙结构。然而坝面隔墙位于消力池水跃跃首位 置，水流流态十分复杂，其动力响应和稳定性问题十分突出。针对工程实践中的隔墙安全问题，本文 基于模型试验并结合数值模拟，分析了该坝坝面隔墙在复杂工作条件下的静动力特性，讨论了其结构 特征与流激振动安全性之间的关系，并对其的稳定性进行了评价，得出结论:该工程泄槽隔墙在结构 设计时应采取适当措施予以加强，且研究成果可为今后类似工程提供参考。     

Hydrologically Based Environmental Flow Methods Applied to Rivers in the Maritime Provinces (Canada)

The demand for water withdrawal continues to increase worldwide. These water withdrawals from rivers can affect fish habitat and aquatic life. As such, environmental flow assessment methods are used in order to protect rivers against excessive water withdrawals. The concept of environmental flow relates to the quantity of water required in rivers to sustain an acceptable level of living conditions for aquatic biota at various phases of their development. For many agencies, environmental flow methods are essential in environmental impact assessments and in the protection of important fisheries resources. The present study deals with the evaluation of hydrologically based environmental flow methods within the Maritime Province of Canada. In total, six hydrologically based environmental flow methods were compared using data from 52 hydrometric stations across the region. Some methods provided adequate environmental flow protection (e.g. 25% mean annual flow and Q₅₀ flow duration method); however, other methods did not provide adequate flow protection (e.g. Q₉₀ flow duration method and 7Q10 and 7Q2 low‐flow frequency). The 70% Q₅₀ method provided adequate flow protection only under good baseflow conditions and should be applied with extreme caution. The present study shows the importance of the hydrologic flow regime, particularly as it pertains to the baseflow component, as a significant determinant in the level of instream flow protection. © 2014 Her Majesty the Queen in Right of Canada. River Research and Applications © 2014 John Wiley & Sons, Ltd.     

AN APPROACH IN MODELING TWO-DIMENSIONAL PARTIALLY CAVITATING FLOW

1. INTRODUCTIONCavitation is a phenomenon that widely occurs in liquids. When the flow leads to the local pressure below the saturation vapor pressure of water (the fluid medium, in our research), usually incipient cavitation firstly occurs on the solid b…     

Application of the ‘natural flow paradigm’ in a New Zealand context

The natural flow paradigm (NFP) emphasizes the need to partially or fully maintain or restore the range of natural intra‐ and interannual variation of hydrologic regimes to protect native biodiversity and the evolutionary potential of aquatic, riparian and wetland ecosystems. Based on our studies of natural and managed flow regimes in New Zealand, we do not believe that all components of the natural flow regime are necessary to achieve the objectives of the NFP, either partially or fully, because many aquatic species have very flexible niches and life‐history requirements (i.e. there is ‘ecological redundancy’). Obviously, maintaining the natural flow regime will maintain the hydrologic and hydraulic conditions necessary for sustaining natural ecosystems. However, if there is adequate knowledge of what ‘values’ need to be maintained in a waterway, and the aspects of the flow regime that are required to maintain those values are also known, then regimes can be designed that target these requirements and thus optimize conditions for the ‘values’. We believe that an assessment of ecosystem requirements using information on river processes together with habitat requirements and life‐history strategies of biota can achieve the best balance between resource use and sustaining ecosystem function and value, and show examples where changes to natural flow regimes have maintained, or even improved, instream values in some New Zealand rivers. We caution that simple flow‐based rules, such as those that might be developed under the NFP, could be unnecessarily restrictive on multiple use of water in New Zealand while, at the same time, preclude the opportunity for enhancement of key ecosystem values in many waterways. Copyright © 2008 John Wiley & Sons, Ltd.     

台阶式溢流坝中小流量流态改善方式研究

台阶式溢流坝有显著的掺气效果和消能效果,目前在中小型工程中广泛应用。但是台阶式溢流坝在小流量浅水深的工况下,坝面上流态较差,呈现跌流或者过渡流态,容易形成水翅和水流跃离现象。为了解决上述问题,本文结合某工程通过水工模型试验研究对台阶起始端的体型进行优化,结果表明优化方案能够很好地改善较小流量时的过渡流态。     

中小型泄水工程利用附着混合流消能问题的探讨

本文介绍了混合流的概念，结合某一中型水库的试验，观测了混合流在抬高尾水时的下游流态。流速分布的变化规律以及对消能效果的影响。从而说明了低水头泄洪建筑物利用挑流消能有更多的可能性。     

均匀来流中振动圆柱尾迹涡结构的数值研究

本文从涡量流函数形式的N-S方程出发,对于不同的振动频率、振幅,首次数值研究了均匀来流中沿任意方向(参见图1,0°相似文献   

无旋流研究

本文将变分法和流网相结合,从理论上证明了无旋流条件下流量达到极大值,并总结出流量达到极大值时,下游流动的两种表现形式:临界流和均速流。文中给出了下游流动分别为临界流和均速流两种情况下的7个实例。在无旋流条件下,应用本文的结果可以进行如下两种情况的计算:(1)利用求极大值来求流量;(2)当流量已知时,如果下游流动为临界流,则可求水深及流速;如下游流动为均速流,则可求流速等。     

ON THE CALCULATION OF FLOW OVER AND THROUGH A ROCK-FILL DAM

1.INTRODUCTIONInthedesignofanovertoppedrock--filldam,oneofthemajortasksistodecidethesizeofthedownstreamprotection.Theovertoppedrock--filldamismadeofporousmedia,thereforethewaterwillpenetrateintothedamfromtheupperfaceandemergeoutofitfromthelowerpart,whileitflowsoverthedam.Hence,theprotectionissubjectedtotheactionofboththeoverflowandtheseepageflow,andneitherofthemcanbenegligible.Inthiscase,theflowfieldconsistsoftwoparts:theopenflowandtheseepageflow,whichhavedifferentproperties.Infact,forthe…     

直槽流动失稳过程数值模拟的可视化

本文利用计算机可视化的方法对直槽流动的数值模拟结果进行了处理，得到了若干组显示涡量场和涡管运动变化的计算机动画，通过对这些直观的动画进行分析，发现了直槽流动失稳的一些现象，对于流动稳定性的研究具有一定的参考价值。