EXPERIMENTAL STUDY ON TURBULENT DRAG REDUCTION AND SELF-EXCITED VIBRATION OF FLEXIBLE TUBES
柔管自激振动特性与减阻效果的实验研究

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 2mm, 3mm, 4mm, being about 12%, 10%, 9% at the Reynolds number of 17500. This would provide a reference for efficient fluid transportation.