梯形渠道水力最佳断面边坡系数推求

Deduction of optimal cross section and slope coefficient for trapeziod open canal

梯形渠道水力最佳断面的宽深比仅与边坡系数有关，本文利用拉格朗日乘数法推导出梯形明渠最佳的理论边坡系数ｍ＝ｔａｎ３０°。

The ratio of depth to width for hydraulic optimal cross section is only related to the slope coefficient, with the method of Lagrange multiplier, it is deduced that the theoretical coefficient is m =tan 30° .