An experimental study of the fluctuating lift force on groups of two and three cylinders of finite height immersed in a turbulent boundary layer at subcritical Reynolds number has been carried out in a laboratory wind tunnel. A technique which makes use of a pneumatic averaging manifold system has been used to measure the fluctuating force at various levels on an instrumented cylinder. Measurements of RMS lift coefficients and mode generalized lift force spectra in a range of spacing and angle attack are presented. The interference levels depend strongly on the spacing and angle attack. 本文係探討三維圓柱體群(二圓柱及三圓柱)在亞臨界雷諾數值之邊界紊流層流中所受之橫向擾動性載重。本實驗是在風洞實驗室裏完成。
實驗係以壓力氣相平均技巧對圓柱模型做各高度水平層的瞬時擾動性載重量測。各層的擾動性數 據可用來計算其均方根值橫向載重係數並合成為一般化振態橫向載重頻譜。此係數和頻譜均顯示出各圓柱間相互干擾的程度與圓柱間距及流向攻角有密切關係。
Relation:
第四屆水利工程研討會論文集=Proceedings of 4th Conference on Hydraulic Engineering，頁389-404
