摘要
本文首先将能量方程归纳为简单的形式，针对由于缺乏实测资料而使计算叉道糙率的方程组不封闭、无法获得其解的实际情况．提出阻力最小原理，导出补充方程，使方程组得以封闭。
Frist,this paper sums energy equations up as simple form.then,according to the actual conditions which equations of computing roughness of branches is unclosed and the root is not found due to lack of field data.minimum energy loss principle is used and additional equation is induced and the ecluations are closed.
关键词
糙率
分汊河道
河流
非封闭问题
水力计算
roughness unclosed equations,minimum energy loss principie,additional equation.
