柔管与紊流耦合减阻效果的初步研究

为探讨柔管与紊流耦合减阻的初步机理，采用双重管结构及激光传感测位仪，在通过实验确认柔性管与刚体管相比确有紊流减阻效果的基础上，对柔管的紊动振动特性及相应的紊流减阻效果以及二者的相关性进行了实验研究。结果表明：柔管的壁厚越小，管外壁振动的脉动位移越大，无量纲的猝发周期也越大，紊流减阻效果越好；柔管壁外为压力平衡空气且雷诺数约为17 500时,壁厚分别为2，3，4 mm柔管的无量纲猝发周期依次为141，126，105，这将为设计高效的流体输送技术提供了一种实验技术上的选择。

Investigation on Drag Reduction Effect with Coupling of Flexible Tubes and Turbulent Flow

In order to probe the mechanism on friction reducing effect by coupling of flexible tubes with turbulent flow,experimental investigation was performed on effect of turbulent drag reduction,fluctuating vibration characters of tube outer wall and the relations between them,based on experimental examination of effect of turbulent drag reduction in flexible tubes by comparison with turbulent drag in rigid tube by using double-sleeve and laser displacement sensor.The results were found as the follows: the thinner the flexible tubes,the bigger the root mean square of fluctuating displacement at outer wall of the tubes,the bigger non-dimension burst period and the bigger the decrease rate of friction cocfficient by coupling of flexible tubes to turbulent flow.When apply pressure-balanced air on the outer wall,the non-dimension burst periods of the flexible tubes with thickness of 2 mm,3 mm,4 mm,are 141,126,105 at the Reynolds number of about(17 500),respectively.This would offer an experimental technical selection for technological development of efficient fluid transportation.