抄録
In the present study, the authors conduct subsonic wind-tunnel experiments, in order to investigate the effect of the depth-to-width ratio λ on the tumbling of simple two-dimensional rectangular-cross-section prisms. The authors carry out instantaneous angle measurements of prisms' rotation, flow visualisation and velocity measurement using a hot-wire anemometer. As a result, there are two modes at λ<0.6 and λ>0.6. Atλ=0.3-0.5, main vortices are emitted during one rotation, and the cycle of velocity fluctuation is 360°. At λ=0.6-0.8, main four vortices are emitted during one rotation, and the cycle of velocity fluctuation is 180°. Especially, at λ=0.5, we can see transient features. At λ<0.6, momentum deficit Md increases with increasing λ. At λ>0.6, M_d decreases with increasing λ. Then, we can see the maximum of M_d at λ=0.6.
