一様流中における三次元正四角柱の渦励振およびギャロッピングに及ぼす隅欠き・隅切りの効果

抄録

The effect of two kinds of corner-cuttings on vortex-induced oscillation and galloping of three-dimensional square cylinders is investigated in uniform flow. The cross-wind response and vortex shedding frequency are measured on the models with corner-cutting ratios e/d = 0/60 to 20/60, and the mass-damping parameter δ = 0.20, 0.50, 0.75, together with the stationary over-turning moment measurement. As a result, it is found out that although the Strouhal number increases as the increase of coner-cutting ratio resulting in to lower the critical wind speed, the model cutted in right angle with the ratio e/d = 4/60 is most stable, because the vortex-shedding frequency is hardly locking-in until the wind speed becomes 30% higher than the critical. The Den-Hartog's criterion also suggests the adovantage of this particular type of corner cutting.