Experiment On Flow-induced Vibration Of Double Tubes

Fluid vortex sheds as it passes over cylindrical structures,which leads to the structure surface periodic exciting force,and makes the cyclical and more complicated vibration in the structure of elastic tube occur.The problem of fluid-solid coupling vibration of multi-cylinder arrangement is more and more concerned by domestic and foreign scholars.This article is intended for double circular tube structure by using wind tunnel experiment and finite element simulation technology and researches the relationship among the vibration response,velocity,horizontal distance and dislocation distance of the elastic support tube in uniform flow field.The specific research content is as follows:(1)Based on the method and theory of experimental research,the experimental model of flow induced vibration is established.It can be regarded as a rigid tube with fixed branches at both ends of its upstream tube.With spring support at both ends,the downstream tube can carry out elastic vibration in the direction perpendicular to the flow direction.(2)By changing the horizontal distance L/D and the dislocation distance H/D between the two tubes,we study the influence of different spacing on the vibration response of the circular tube structure.The results show that the vibration response of the double-tube structure is different from the single-tube.And the different arrangement of columns(series arrangement or staggered arrangement)shows different response characteristics.When the horizontal distance L/D is smaller,the impact of the upstream tube on the vibration of the downstream tube is smaller,and the critical velocity of the tube is larger.When the dislocation distance H/D=0.25,the vibration wind speed of the elastic tube is the smallest,and the critical velocity and amplitude of the downstream tube decrease with the increase of H/D value(the dislocation distance of the two tubes).(3)Combining the content of experiment,using the finite element analysis software and choosing the appropriate turbulence model,we carry the two-way fluid-structure coupling calculation on the two-dimensional structure mode of tandem double circular tube under the action of the transverse flow,and discuss the relationship among the inflow velocity,the flow field form and the system response.