明渠非定常水流的垂向结构实验研究

THE VERTICAL STRUCTURE OF UNSTEADY OPEN CHANNEL FLOWS

本文报告了明渠非定常水流垂向结构的实验研究,通过 LDV 激光测速,我们给出了非定常水流的速度削面,湍流度,Eulerian质量输运速度的垂向分布。实验结果表明:在非定常周期很长时非定常流动的速度剖面,湍流强度及其粗糙度的影响基本上与定常流动相一致,当非定常流动为纯往复流动时,存在一个逆时针方向的环流,这种环流有利于底部的质量输运。

This paper gives an experimental report about the property of the vertical structure of an unsteady openchannel flow.By the use of the LDV,the vertical distribution of velocity,the turbulent intensity and the Eu-lerian transport velocity of the unsteady open channel flows are known and are given in this paper.The ex-perimental results show that the profile of the open channel unsteady flows,the period-averaged turbulentintensity and the effect of roughness on unsteady flows are similar to those of the steady open channelflows.When the flow is of purely reversible,there exists a residual current which is counter-clockwise andis beneficial to the mass transport near the bottom.