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Practical computational method of open channel unsteady flows including sub ＆ super critical flows

明渠非定常流（包括亚临界流和超临界流）的实用计算方法

基本信息

批准号：
12660215
负责人：
SHIMADA Masashi
金额：
$ 1.54万
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 (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

The explicit scheme, proposed by Moll (1998) using the Saint Venant equations in the conservation form, is advanced toward its establishment of a practical numerical method of computing coexisting subcritical and supercritical flows through analyzing how to incorporate calculations at boundaries. The scheme suppresses spurious oscillation due to numerical errors by incorporating the flux limiter in the easier calculation algorithm. Especially, the calculations at a connection between two channels with each different slope is theoretically analyzed. A set of the finite-dirrerence equations and boundary condition gives two bifurcated relations : one is valid for flows except for critical flows and the other valid for critical flows. With these the explicit scheme becomes hopeful method of analyzing unsteady flows where a control section, a hydraulic jump, and bore are given to examine the analysis on boundary calculations. In addition, connections between two channels of different cross sections such as circular or rectangular ones, where the flows change from ordinary to another ordinary flows, are dealt with to solve the finite-difference equations, the boundary conditions, and the momentum equation proper to the connection boundary. The some computational examples are given by calculations of unsteady flows including supercritical and subcrtical flows situations and/or a bore (translatory jump) in simple and rather complicated channel systems.

通过分析如何在边界处进行合并计算，将Moll（1998）提出的基于守恒型圣维南方程的显式格式推向建立亚临界和超临界共存流动的实用数值计算方法的方向。该方案通过在简单的计算算法中加入磁通限制器，抑制了由于数值误差引起的寄生振荡。特别是对两个不同坡度的渠道连接处的计算进行了理论分析。一组有限差分方程和边界条件给出了两个分叉关系：一个适用于除临界流以外的流，另一个适用于临界流。在给出控制断面、水跃和钻孔的情况下，显式格式成为分析非恒定流的有希望的方法，以检验边界计算的分析。此外，还讨论了两个不同截面的通道（如圆形或矩形通道）之间的连接，其中流动从普通流动变为另一种普通流动，以求解有限差分方程、边界条件和适合于连接边界的动量方程。文中给出了简单和复杂渠道系统中包括超临界和亚临界流动情况和（或）一个孔（突跃）在内的非定常流动的计算实例。