曲率の大きい凹面に沿う乱流壁面噴流の壁近傍における流れ構造の可視化

抄録

The near-wall flow structure of turbulent wall jets has been visualized by smoke-wire method and by tuft-grid method with image processing technique, both along strongly concave and plane surfaces. For the concave surface, the smoke-wire pictures suggest the presence of roll-cell structure wandering randomly in space and time. This structure is also observed in the image processed tuft pictures, which are taken at comparatively high flow Reynolds numbers. On the other hand, the flow visualization of a plane wall jet shows a relatively uniform structure, while it consists of small scale streaks near the wall.