Development of Reasonable Numerical Methods For Predicting Complicated Hydraulic Appearance With Different Time and Space Scales

发展合理的数值方法来预测不同时间和空间尺度的复杂水力形态

基本信息

批准号：
08456116
负责人：
SHIMADA Masashi
金额：
$ 5.06万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

(1)The numerical methods are discussed theoretically and experimentally developed for predicting water surface of one dimensionally varied steady flows in open channels with a regular cross-section and locally varied resistance zone near the one-sided wall. The resistance zone is composed of pile series arranged like vegetation belt or rough stone zone. The lateral distribution of depth-averaged velocity within a cross section is firstly estimated from the equation of motion including the eddy diffusion effects due to interaction between distributed piles. The longitudinal water level is calculated using the one-dimensional energy equation in which the resistance effect of the pile zone is estimated as the lateral velocity distribution. The comparisons between the experimental and calculated values with respect to the velocities and water levels are very good to examine the usefulness of the analyses. The similar method is extended to the channels with compound sections. With that meth … More od, the cross sections of the flow were divided into three regions to predict the distribution of velocity and water level. With the previous methods the lateral velocity distribution assumes the uniform flow condition while we assume non-uniform flows. The longitudinal water level can be predicted by using the lateral velocity distribution and the energy slope obtained from that velocity distribution. The calculation method is validated by comparisons of the results obtained from the experiments made in the channels with regular and compound sections under the conditions of several kinds of pile zones.(2) To design reasonably grids for slow and rapid transient analysis using the method of characteristics is required to estimate the errors due to the discretizations and lime-line interpolations. The discretization errors for the linear valve closure problems in the simple piping systems is numerically and theoretically investigated with respect to pressure head rises, and formulated as the non-dimensional semi-theoretic equation, which is a function of the time scale of waves(valve closure time), pipe length, wavespeeds, number of pipes, and frictional coefficients. The combined time-line method for slow and rapid transient analysis is offered through designing adequate time-step sizes and grids, which satisfy the criteria for the discretization error and the error du to time-line interpolations. It is examined by numerical computations of transients using the pipeline model. Less

（1）讨论了理论和实验性开发的数值方法，用于预测一个尺寸变化的稳定流的水面，该稳定稳定流动在一个正常的横截面和局部变化的电阻区附近附近。电阻区由桩序列组成，如植被带或粗糙的石区。首先是根据运动方程估计深度平均速度的横向分布，包括由于分布式钢琴之间的相互作用而引起的涡流扩散效应。使用一维能量方程计算纵向水位，其中堆积区的电阻效应估计为横向速度分布。相对于速度和水位的实验值和计算值之间的比较非常好，可以检查分析的有用性。类似的方法扩展到具有复合部分的通道。使用该方法……更多的OD，将流的横截面分为三个区域，以预测速度和水位的分布。使用先前的方法，横向速度分布假设流动条件均匀，而我们假设流动不均匀。可以通过使用从该速度分布获得的横向速度分布和能量斜率来预测纵向水位。通过比较在几种桩区域的条件下，从通道中与规则和复合部分进行的实验获得的结果进行比较来验证计算方法。（2）为了设计合理的基础，以进行缓慢和快速的瞬态分析，以估计由于iPtizatisation和lime inime inmepolations估算错误的特征。在简单管道系统中，线性阀封闭问题的离散误差在数值和理论上都在压力头上升方面进行了研究，并以非二维半理论方程式配制，这是波浪时间尺度（阀门闭合时间），管道长度，管道长度，波动器，波管，管道，管道和弗里克特系数的函数。通过设计足够的时步尺寸和网格来提供缓慢和快速瞬态分析的组合时间线方法，该方法满足了离散误差的标准以及时间线插值的误差DU。通过使用管道模型对瞬变的数值计算来检查它。较少的