Abstract
Behavior of wall wake behind a two-dimensional flat plate placed perpendicularly on a ground plane was experimentally investigated with the aid of a laser Doppler velocimetry. The experiment was performed for three types of flat plates with the height of H = 15 mm, 20mm and 40mm. From distribution of iso-velocity lines in a cross-stream plane, we found that two-dimensionality of the velocity field in wall wake region was not achieved for low height flat plate. This trend was observed at the streamwise location X ≦ 20H. Velocity vectors in the horizontal plane indicated that a flow over the flat plate generated two vortices near both side walls and the recirculation region was reduced with increasing in the ratio of the plate height H to the tunnel height h (H/h). These phenomena caused difficulty of realizing the two-dimensionality of the velocity field in the wall wake region.
