抄録
Roughness effects on the turbulence structures over a two-dimeansional rough hill are investigated experimentally and numerically in this study. The hill concerned has a maximum slope of about 32゜ with a seperation bubble formed at its leeside. The results of smooth wall condition and rough wall condition (roughness density 45%) are compared to make clear the roughness effects. On the rough wall condition, the reattachment length is getting longer, and the wake flow is influenced by the oncoming turbulence within a longer region. The power spectrum of the velocity fluctuation measured at the wake region decreases in the low frequency regime and increases in high frequency regime much more than on the rough wall condition.
