一端弹性支撑的串列双柱和并列双柱在气流中自由端的振幅响应

本文研究了一端弹性支撑的并列双柱和串列双圆柱在气流中自由端的振幅响应，与单圆柱相比，在小间距时，串列双圆柱中前柱的横向振幅受到较强的激励。而在大间距时，振幅受到抑制，特别当Ｌ／Ｄ＝３．５和４．０时，其振幅响应仅为单柱的１／３左右，而对于后柱，则在大间距时，纵向振幅响应有所增大，而且后柱的振幅响应要比前柱的大得多，而并列双圆柱的自由端振幅基本上受到抑制，在Ｔ／Ｄ＞３．０之后，干扰很快减小到接近单个圆

THE RESPONSE AMPLITUDES OF THE TWO FREE ENDS OF TWO FLEXIBLE CANTILEVER CYLINDERS ELASTICALLY SUPPORTED THE OTHER ENDS PLACED IN-TANDEM OR IN PARALLEL IN AIRFLOW

In this paper, the response amplitudes of the two free ends of two flexible cantilever cylinders with the other ends elastically supported placed in tandem or in parallel in airflow arc ?studied.In the experiment, more attentions were paid on the comparisons of the amplitudes of two cylinders in various spacing ratios with that of the single cylinder in airflow.When two cylinders are in tandem, the transverse oscillation of the upstream cylinder is excited in the range of L / D < 2. 5, but it is restrained in the range of L / D = 3.0. Especially for L / D = 3.5 and 4. 0 the response amplitude is only one third to that of the single cylinder.When two cylinders are in tandem, the longitude oscillation of the downstream cylinder is greater than that of a single cylinder when the range of spacing L/ D>3.0 and is also greater than that of the upstream cylinder.For two cylinders are in parallel ( side- by- side) , the response amplitude is restrained for the small spacing. When the spacing ratio is greater than 3.0, these are very close to that of the single cylinder. It means that the interference between two cylinders reflecting on the response of oscillation are vanished.