振動するく形断面柱に作用する流体力特性 : 流れと直角方向に振動する場合

概要

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Measurements were made of the time-averaged and fluctuating fluid forces, vortex-shedding frequency and wake structures of rectangular cylinders forced to oscillate transversely at a maximum amplitude of 10% of the length of the front face. The ratio of depth (streamwise dimension) to height (cross-stream dimension) of the cross section ranged from 0.3 to 1.0. The nondimensional frequency F_vH/U_0 (F_ν : frequency of forced oscillating cylinder, H : height of cylinder, U_0 : free-stream velocity) was varied from about 0.08 to 0.20, in which the lock-in region was included. It has been found that a critical depth where the fluid forces attain a peak in the oscillating cylinder is smaller than that of the stationary cylinder. Also, within the lock-in region in which the vortex shedding is perfectly synchronized with the force frequency F_ν of the cylinder only, the fluid forces are found to attain a maximum. Furthermore, it is recognized that the work done by the fluctuating lift changes to positive work, which induces the generation of negative aerodynamic damping from negative work when the ratio of depth to height is smaller than 0.5.
一般社団法人日本機械学会の論文
1994-04-25