中文摘要：

为了提高准二维管道瞬变流模型的计算效率,对现有的基于特征线法的准二维模型的算法进行了改进,提出了直接利用一维显式方程计算管道的流量和压力,取代了原算法中需通过数值积分求解平均速度再进一步计算节点压力的方法。该文提出的一维显式方程采用FVS（Flux Vector Splitting）方法,并在水库-管道-阀门系统中,将该方法与两个现有的准二维模型的算法在准确性和计算效率方面进行了比较。结果表明：该文所提出的方法与另外两个算法得到的计算结果基本相同,但是所花费的计算时间更少。因此,该文所提出的方法是一种计算准确并且高效的准二维瞬变流计算方法,适用于管道系统瞬变流的数值模拟分析。

英文摘要：

In order to increase the computational efficiency of quasi-two-dimensional （quasi-2D） water-hammer models, a method that improves upon an existing quasi-2D scheme in the method of characteristics （MOC） is presented. The proposed method uses one-dimensional （1D） explicit equations to calculate pressure head and discharge, rather than using numerical integration to solve mean velocity as employed in the existing scheme. The 1D explicit equations are developed, based on the flux vector splitting （FVS） method. In a reservoir- pipeline-valve system, the comparisons between the proposed method and two existing quasi-2D schemes show that the proposed method gives virtually the same results as the other two quasi-2D schemes do, but costs less computational time. Therefore, the proposed method is able to simulate transient flow problems with high accuracy and efficiency.