在这研究,在稳定的流动的一条僵硬飞机边界附近的柱体的导致旋涡的颤动试验性地被学习。僵硬飞机边界附近的柱体的导致旋涡的颤动的现象在斜槽被复制。流频率和模式的旋涡被热电影速度计和氢水泡的方法也测量。参量的研究被执行在振幅和柱体的频率回答上调查减少的速度, gap-to-diameter 比率,稳定性参数和集体比率的影响。试验性的结果显示:(1 ) Strouhal 数字(圣) 为在亚 critical 流动政体的一条飞机边界附近的静止柱体在 0.2 附近;(2 ) 与增加 gap-to-diameter 比率(e 0/D), 振幅比率(A/D ) 变得更大但是频率比率(f/f n ) 为 e 0/D (0.66 在这学习的 e 0/D 】 ) 的更大的价值的案例有一个细微变化;(3 ) 有振幅的清楚的差别和在更大的 gap-to-diameter 比率之间的柱体的频率回答(e 0/D 】 0.66 ) 并且更小的(e 0/D 【 0.3 ) ;(4 ) 柱体的颤动更容易发生并且颤动的范围以 V r 数字与稳定性参数,而是频率反应的减少变得更广泛被稳定性参数稍微影响;(5 ) 与减少的集体比率,占据的宽度以 V r 并且频率比率(f/f n ) 变得更大。
In this study, the vortex-induced vibrations of a cylinder near a rigid plane boundary in a steady flow are studied experimentally. The phenomenon of vortex-induced vibrations of the cylinder near the rigid plane boundary is reproduced in the flume. The vortex shedding frequency and mode are also measured by the methods of hot film velocimeter and hydrogen bubbles. A parametric study is carded out to investigate the influences of reduced velocity, gap-to-diameter ratio, stability parameter and mass ratio on the amplitude and frequency responses of the cylinder. Experimental results indicate: (1) the Strouhal number (St) is around 0.2 for the stationary cylinder near a plane boundary in the sub-criti- cal flow regime; (2) with increasing gap-to-diameter ratio (eo/D), the amplitude ratio (A/D) gets larger but frequency ratio (f/fn) has a slight variation for the case of larger values of eo/D(eo/D 〉 0.66 in this study); (3) there is a clear difference of amplitude and frequency responses of the cylin- derbetween the larger gap-to-diameter ratios (e0/D 〉 0.66) and the smaller ones (e0/D 〈 0.3); (4) the vibration of the cylinder is easier to occur and the range of vibration in terms of Vr number becomes more extensive with decrease of the stability parameter, but the frequency response is affected slightly by the stability parameter; (5) with decreasing mass ratio, the width of the lock-in ranges in terms of Vr and the frequency ratio (f/fn) become larger.