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     

伊朗迪兹拱坝的再分析

本文对迪兹拱坝的静力和动力再分析结果进行了讨论。这座203.5m高的双曲拱坝,位于地震活跃的扎格罗斯山脉,是目前亚州最高的拱坝。该坝的特点之一是用周边缝把坝体与混凝土鞍座结构分隔开。采用滑移和无拉伸能力的曲线等参数接缝单元进行了非线性静力分析。还做了校正分析。由于库水位的变化,拱冠悬臂梁的径向变位是通过优化大体积的弹性模量进行校正的。最后,本文探讨了最大可信地震的非线性动力分析结果。使用破坏指数叙述了诱发地震的破环,该破坏指数可对不规则应力时程的不同类型进行比较。严密的分析表明,采用现代设计标准比用试载法得出较高的应力。     

欧文瀑布电站采用预应力锚束进行加固

乌干达欧文瀑布电站发电机周围的混凝上产生裂缝,采用预应力锚束进行加固,施工时电站仍继续运行。本文叙述了锚束设计和试验的有关情况。欧文瀑布大坝及电站隶属乌干达电力局,建在里彭瀑布(被称为尼罗河发源地)的下游、欧文瀑布的上游。在水轮机及蜗壳四周为大体积混凝上,柱、墙均为钢筋混凝上。水轮机上部的柱体混凝上中埋入钢结构。以钢屋架支承预制混凝     

奇拉水电站水轮机叶片新的设计原理

奇拉水电站水轮机叶片新的设计原理Ａ·斯瓦罗普等主题词：转浆式水轮机，水轮机设计，水轮机导水机构，水轮机振动，模型试验，水轮机磨损，成因分析，防护措施奇拉（ｃｈｉｌｌａ）水电站的转浆式水轮机的关键部件——转轮叶片，由于泥沙反复磨损，在叶片出水边附近的叶...     

运用注水—抽水井系统控制海水入侵

动用垂面上集合的二维突变界面模型，对采用注水抽水井系统控制海水的技术的进行了研究，依据加勒金加权残余数法在建立了模型并运用现行的解析解对模型作了验证，对模型参数作了无量纲处理，并进行了一系列的参数研究以获得单独运用抽水帷幕和抽水－注水并用情形下的特性曲线，这些曲线可以用于评价输入参数的海－淡水界在的趾端位置的影响。     

A BOUNDARY INTEGRAL EQUATION AND ITS NUMERICAL SOLUTION OF POTENTIAL FLOW AROUND SURFACE-IRREGULA-RITIES

In this paper,using complex functional theory,the authors turn the potentialflow around the surface irregularities in a pressure conduit and semi-infinite platforms intoDirichlet problem.Based on Schwarz formula and by the application of Plemelj's formula,theauthors change the problem into the integration of a Cauchy boundary integral equation in theflow plane through the substitution of variables.Using numerical integration,the authors obtainthe velocity distribution and pressure coefficient along surface irregularities and platforms.Thephysical concept of this method is clear,the convergent speed is rapid and the computative effi-ciency is high.The calculated values agree well with the measured results.It is an effective andsimple method in solving potential flow.