明渠恒定渐变流底坡计算研究

How to Calculate Slope of Open Channel with Theory of Steady Gradually Varied Flow

在渠道设计中,通常按明渠均匀流计算渠道底坡。当渠道较短时,不能形成均匀流,则需按恒定渐变流理论计算渠道底坡,至今尚未发现探讨该类问题的文献。因此本文结合工程实例,分析了四种类型的水面线和渠道底坡间的关系,以及相应的底坡搜索区间,最后用性能稳健的二分法计算出了渠道底坡值。

In design of an open channel, the slope of channel is usually designed by the theory of uniform flow of channel. When the channel is so short that flow in it can not become uniform flow, it must be calculated with the theory of steady gradually varied flow. By now, no paper is found to have discussed this problem . So in this paper, an analysis was given about the relation between flow profile and slope of channel based on the engineering examples, referring to four types of flow profile, and variable searching region was concluded. Finally the robust dichotomy method was used to calculate the value of slope of channel.