明渠均匀流弗劳德数随水深的变化规律

Variation Law of Fr Number with Depth of Water in Open Channel Uniform Flow

弗劳德数(Fr)是判别明渠水流流态的标准,掌握弗劳德数随明渠水深的变化规律,对认识明渠水流的流态特性、指导明渠的设计具有重要意义。从弗劳德数Fr的定义出发,通过理论计算分析明渠均匀流弗劳德数Fr随水深的变化规律,分别揭示了矩形、梯形和圆形断面明渠均匀流弗劳德数Fr极大值的存在条件及变化特征。分别列举算例对计算结果进行验证,为今后工程实际中通过控制断面水深来控制流态提供了依据。

Fr number is the discriminating standard for flow regime of open channel flow.Mastering the variation of Fr number with the depth of water has important significance to understand the flow characteristics of open channel and design open channel.According to the definition of Fr number,the variation of Fr number in open channel flow with the depth of water was analyzed by theoretical calculation.The existence conditions and variation characteristic of the maximum value of the Fr number in rectangular,trapezoidal and circular cross-section channel were revealed.The calculation results are verified by examples.Thus,it provides a basis for control of flow regime by regulating the depth of water in actual project in the future.