在进行渠道水力计算的过程中,当流量 Q、渠道底坡 i 及糙率 n 已知的情况下,都希望得到最小的过水断面面积,以减少土石方开挖量,或者说,在过水断面面积、渠底坡度和糙率一定的条件下,使渠道所通过的流量最大.水力学中把满足上述条件的断面形式叫做水力最优断面. In the process of channel hydraulic calculation, when the flow rate Q, channel slope i and roughness n are known, all hope to get the minimum cross-sectional area of ​​the water to reduce the amount of earth and stone excavation, or in the water Section area, bottom slope and roughness under certain conditions, so that the maximum flow through the channel.In hydraulics to meet the above conditions of the cross-section form called the hydraulic section.