摘要
在满足恒定流、正坡、长而直的棱柱体、粗糙度不变化4个条件时才会有均匀水流出现,水工建筑物(桥涵)干扰均会产生非均匀流。其总水头线、水面线、底坡线沿程很难相等,工程设计人员往往采用明渠均匀流的近似值来计算过水断面的流量能力,未考虑局部过水断面的较小突变引起附加阻力消耗的机械能。考虑到河道防洪能力、汛期排涝等安全因素的重要性,采用拟非均匀流计算方法更逼近现实情况。
Only meeting the four conditions including steady flow, positive slop, long & straight prismoid and unchangeable roughness, will the uniform water flow appear. And the non-uniform water flow will always appear due to the distraction from the hydraulic structures(bridges & culverts). The total head line, water line and the bottom slope line along the main stream are difficult to be equal, but the engineers are often used to calculate the flow capacity of the section water by the model of uniform flow in open channel without considering the mechanical energy loss caused by the block of small local mutation of the cross section. Related to the importance of the capacity of the anti-flood and the water-logging of the river, the calculation method to the equivalent non-uniform flow used in this paper is more close to the reality of the situation.
出处
《中国市政工程》
2015年第5期20-21,25,共3页
China Municipal Engineering
关键词
桥梁
明渠非均匀流
局部水头损失
过水能力
bridge beam
non-uniform flow in open channels
the local head loss
capacity of water flow
