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

（1）从理论和实验两方面探讨了在具有局部变阻力区的规则断面明渠中一维定常变化水面的数值计算方法。阻力区由桩系组成，呈植被带或乱石带状排列。首先从考虑分布桩间相互作用引起的涡动扩散效应的运动方程出发，计算了桩周水深平均流速的横向分布。纵向水位的计算采用一维能量方程，其中桩区的阻力效应被估计为横向流速分布。流速和水位的实验值和计算值之间的比较是非常好的，以检查分析的有用性。将相似方法推广到复式断面渠道。用那些冰毒 关于我们 od，将水流断面分为三个区域，预测流速和水位的分布。与以前的方法横向速度分布假设均匀流的条件下，而我们假设非均匀流。利用流速的横向分布和由该分布得到的能量斜率，可以预测纵向水位。通过对几种桩区条件下的规则断面和复式断面渠道试验结果的比较，验证了计算方法的正确性。(2)采用特征线法进行慢瞬态和快瞬态分析时，需要合理地设计网格，以估计离散化和直线插值所引起的误差。对简单管道系统中线性阀门关闭问题的离散化误差进行了数值和理论研究，并将其表示为无量纲的半理论方程，该方程是波的时间尺度（阀门关闭时间）、管道长度、波速、管道数目和摩擦系数的函数。通过设计适当的时间步长和网格，满足离散误差和时间线插值误差的准则，提出了一种适用于慢、快瞬态分析的联合时间线法。它是检查使用管道模型的瞬态数值计算。少

(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