1001 角柱の流動誘起振動に及ぼすT型フィン設置による振動抑制効果(OS10-1 流体関連振動・騒音,オーガナイズドセッション)

Abstract

Wind tunnel experiments are carried out to investigate the interference effect of T-shape fin on the galloping of square cylinder with a side length d. As the T-shape fin, a rectangular-plate of spanwise width w=d and cross flow height l_d is fixed to the downstream side of the square cylinder at the mid span with a thin bracket plate. The gap between the plate and the cylinder is adjusted by the bracket length s. T-shape fin of l_d/d<2.0 effectively suppress galloping when 1.4<s/d<2. While, T-shape fin of 1.0<l_d/d<1.5 induce the large amplitude vibration when s/d<1.4. Maximum amplitude of this vibration becomes about 2.2 times of galloping at around s/d=0.3. The amplitude at s/d=03 increases divergently with flow velocity. This oscillation is called "Wake Body Interference Fluid Elastic Vibration (WBIFEV)" to be reasonable, because this vibration is caused by the fluid-elastic instability but not by a periodic vortex shedding.