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.

Moll（1998）使用“保护形式”中提出的显式方案是为了建立一种实用的数值方法来计算通过分析如何在边界上合并计算的实用数值方法。该方案通过将通量限制器纳入更轻松的计算算法中，从而抑制由于数值错误而引起的虚假振荡。特别是，在两个通道之间与每个不同斜率之间的连接上的计算进行了理论分析。一组有限的方程式和边界条件给出了两个分叉关系：一个对流量有效，除了关键流，另一个对关键流有效。通过这些，显式方案成为分析不稳定流动的有希望的方法，在控制部分，液压跳和孔中可以检查边界计算的分析。此外，处理不同横截面的两个通道之间的连接，例如圆形或矩形的连接，其中流量从普通流变为另一个普通流，以求解有限差分方程，边界条件以及适当的连接边界的动量方程。一些计算示例是通过在简单且相当复杂的通道系统中的不稳定流动的计算以及包括超临界和亚克式流动情况和/或孔（翻译跳跃）的计算。