柔管自激振动特性与减阻效果的实验研究

EXPERIMENTAL STUDY ON TURBULENT DRAG REDUCTION AND SELF-EXCITED VIBRATION OF FLEXIBLE TUBES

为弄清柔管自激振动的湍流减阻效果的初步机理,在通过实验确认柔管确有湍流减阻效果的基础上,采用双重管结构和激光测位仪,对柔管的自激振动特性及湍流减阻效果及其两者的关系进行了实验研究．结果表明:管的壁厚越小,管外壁的自激振动的脉动位移有效值越大,湍流减阻效果越好;管壁外为压力平衡空气且雷诺数约为17500时,壁厚为2mm,3mm及4mm柔管的自激振动减阻率依次约为12％,10％,9％．这将为开发有效的管道流体输送技术提供参考．

To clarify the relation between turbulent drag reduction and self-excited vibration of flexible tubes, experiments were performed on the effects of turbulent drag reduction and the characters of self-excited vibration, by comparing the turbulent drag with that in a rigid tube and by using a double-sleeve structure and a laser displacement sensor. The results are as the follows： the thinner the flexible tubes, the larger the root mean square of the fluctuating displacement at the outer wall of the tubes, and the larger the decreasing rate of the friction coefficient of the self-excited vibration, while applying a pressure-balanced air on the outer wall, with the rates of drag reduction of the flexible tubes with thickness of 2 mm, 3 mm, 4 mm, being about 12%, 10%, 9% at the Reynolds number of 17 500. This would provide a reference for efficient fluid transportation.