明渠流速分布经验公式及其在高洪测流中的应用

对二维明渠均匀流流速分布公式进行修正,根据普朗特半经验半理论流速分布公式导出二次抛物线分布的经验公式,并由此公式推导出表面流速与平均流速的关系,经实验室及天然河流7个水文站实测流速分布资料验证,其相对误差在2%以下,满足工程界的精度要求,这对减少洪水期测流的工作量,提高测流的精度具有实际应用价值。

An Experiential Formula of Velocity Distribution in Open Channel Flows and Its Application in Flow Measurement in High Flood

A modification is made for the velocity distribution formula of two-dimensional open channel uniform flows. Based on the Prandtl's momentum transfer theory, a new law on the distribution, i. e., the experiential formula of biparabola distribution is obtained. Therefore, the relations between the free surface and the mean velocity, and between the maximum and the mean velocity on an erect line are derived. They are checked by the experimental data in the laboratory and in seven Hydrometric stations of four rivers in the south of China. The first relation is better than the second one, and its relative error is less than 2%. As a result, the biparabola formula can be used in measuring velocity only on the surface of water, accordingly determining the flow discharge through the channel or river in the flow measurement in high flood.