Abstract
Tracer method was applied to visualize the three-dimensional structure of turbulent open-channel flow. The horizontal cross-section of the flow illuminated by light through thin slit was shifted upward and downstream. At the same time, pictures of flow patterns were taken every half a second by the camera mounted above the channel. Illuminated cross-section and the camera were both shifted downstream with mean velocity of the flow. Pictures obtained were processed by computer system and distribution of velocity vectors, rotation and two-dimensional divergence were displayed concerning each horizontal cross-section of the flow.
On the basis of these results, downward or upward motion of fluid such as boils, bursts or sweeps were illustrated precisely and their distribution in three-dimensional flow field and their relation with eddy motions were made clear.
