1998年松辽流域特大洪水灾情分析

１９９８ 年松辽流域发生了特大洪水， 其直接经济损失计为５５４．４２８ ２ 亿元。通过按流域统计， 行政区划统计计算灾害情况的研究分析， 提出了今后东北地区防洪减灾的方向与目标。     

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美国陆军工程师团经管运行的有344台水轮机,有些水轮机运行已超过50年。某些机组曾经历过重大的运行问题。为获得满意的解决,在工程师团成员、设计者、制造者和运行人员之间的有效合作是必需的。美国陆军工程师团已建成的水力发电设施遍布全美国,现在仍有70％在运行。其规模可从弗吉尼亚州罗诺克河上的14MW费尔波特水电站起,到位于华盛顿州和俄勒冈州哥伦比亚河上的2200     

SIMILARITY LAW OF FLUCTUATING PRESSURE WITHIN HYDRAULIC JUMP AREA

Through a series of model tests of five scales for 2-D free hydraulic jump, the da-ta of fluctuating pressure acting on the floor level within the hydraulic jump were obtained. Dur-ing the experiments, Froude number varied from 2.94 to 8.61, and Reynolds number rangedfrom 2×10~4 to 6×10~5. Experiment results indicate that the amplitude scale of fluctuating pres-sure is the length scale of model, i. e. P'=L, which agrees with gravity similarity law: Thefrequency scale of the fluctuating pressure is a unity i. e., f=1, which does not satisfy thegravity similarity law.     

THE FLOW PRODUCED IN PARTICLE-SUSPENSION BY AN INFINITE ROTATING DISK:SERIES SOLUTION

To the flow produced in particle-suspension by a rotating disk of infinite extent,the asymptotic behavior at infinity is analyzed.A corresponding series solution is presented.It isshown that this approach yields widely valid solutions of high accuracy for all the cases in whichthat suction or weak injection at the disk surface exists.For the cases that strong injection or par-ticle-free band exists,the series method fails.     

TURBULENCE MEASUREMENT INSTRUMENT WITH A SILICON PIEZORE-SISTANCE BEAM

A newly developed turbulence measurement instrument is introduced in the paper.The transducer of the device is based on the principle of the effect of silicon piezoresistance that isintegrated in a Wheatstone bridge on a pure silicon beam. At one end of the beam, a small lightball is installed as the target forced by the water flow. The other parts are prevented from thewater flow with a sophisticated stainless steel tube. The instrument can be used to measure turbu-lent velocities either in clear Water or in flows bearing hyperconcentration of sediment. It can al-so be used to measure velocities in both glass flume and model experiments as well as in pipe ex-periment by being mounted in a special way.     

提高动力问题直接积分法的精度

一、概述在结构动力分析中,广泛采用直接积分法求解时域内的运动方程。主要的方法分两类。第一类为显式方法。即将加速度和速度用连续的位移值表示,在运动方程中,加速度和速度被每一时间步长内所要求出的位移矢量所代替。这类方法的主要区别在于有各种不同的假定,它们的—个主要缺陷就是它们是条件稳定的。事实上可以说明所选时间步长增量必须远     

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扎戈尔抽水蓄能电站施工经验

扎戈尔抽水蓄能电站施工经验Ｂ．Ｍ．普洛特尼科夫Ａ．Ａ．贝卡多罗夫主题词札戈尔抽水蓄能电站，施工技术，施工组织设计，运行可靠性扎戈尔抽水蓄能电站是俄罗新第一座大型新式蓄能电站，其设汁装机容曾为１２０万ｋ＼Ｖ（已装机８０万ｋｗ）。前苏联水工建筑设汁院在技...     

水库回水计算的几点体会

水库回水计算成果是确定水库淹没处理范围的依据，关系到水利水电工程正常蓄水位和汛期限制水位的合理选定。因此，提高水库回水计算精度是一个重要的课题。影响水库回水计算成果和精度的主要因素是：河道断面特性值Ｆ，沿程糙率ｎ，河段计算流量Ｑ以及上下断面间河段距离△Ｌ；要使这些因素正确合理就要合理布设断面，提高测量精度，应用计算机划分主边槽，深入细致地分析研究沿程糙率ｎ。