Y型汇流口壅水规律研究

Pattern of backwater at a Y-shaped junction

将Y型汇流口划分为直段与汇流段,在直段建立能量方程,在汇流段建立动量方程,并以此建立了一维数学模型,试验证明该模型可以成功预测Y型汇流口水流状态.结合因次分析,利用该模型对Y型汇流口各主要水力控制因素进行了分析,结果发现:在平底Y型汇流水槽,随着汇流比Qr增大,水深比Hr先增大后减小;当汇流角α为锐角时,Hr变化不大,但是当α超过90°以后,随着α的增大,Hr急剧增大;随着下游干流弗劳德数Frd增大,Hr增大;下游干流宽深比Wd/Hd,k1,k2越大(水流越宽浅),Hr越小.

A Y-shaped junction was divided into straight section and junction section. Energy equation for the straight section and momentum equation for the junction section were established. It was proved by experiments that the mathematical model could predict the hydraulic phenomena of the Y-shaped junction successfully. According to the dimensional analysis, some hydraulic factors that control the current of Y-shaped junction were analyzed. Results indicate that, in Y-shaped junction flume with flat bottom, the water depth ratio of the upstream mainstream channel to the downstream channel Hr increases first and then decreases when the discharge ratio of mainstream to post-confluence channel Qr decreases; Hr has little change with the increase of a when the junction angel a was less than 90°, but when it surpasses 90°, Hr increases sharply. Hr increases with the Froude number Frd of lower mainstream. When the width to depth ratio Wd/Hd of the lower mainstream increases as well as the width ratio of the upstream mainstream channel to the downstream channel kl and the width ratio of the upstream tributary channel to the downstream channel k2, Hr decreases.