多孔管水流流态的变化对水头损失计算的影响

大量计算表明，灌溉中使用的小流量多孔管的首端流态一般是紊流光滑区和紊流过渡区，而在末端或多或少出现一定长度的层流段。管内流态的变化会影响水头损失的计算。但是普遍认为这种影响是很小的，至于小到什么程度，目前还没有人提出一个数量范围。本文主要分析多孔管水流流态，并使用计算机模拟了流态变化对水头损失计算的影响。

The Influence of the Type of Flow in Perforated Pipe on Calculating Water Head Losses

It ha been shown that the turbulent flow appears at the beginning of the pipe,and laminar flowat the end.The type of flow would affect the calculation of water head losses.It is,in generally speaking,very small,but nobody knows how much it is. In this paper,thetype of flow in perforated pipe was analysed,and the influence of which on calculating waterhead losses was simulated by computer programme.