Author(s): N. Tamoto; A. Tominaga; K. Ijima
Linked Author(s):
Keywords: PIV; Continuous spur dike; Orientation angle; Flow structure; Turbulence
Abstract: The flow structures around the continuous spur dike were investigated by using the PIV method, changing the orientation angle of the spur dike. In this study, the orientation angle and the location of the spur dike were chosen as a control parameter. The orientation angle was varied in three ways. The visual images were recorded by a high-speed camera and analyzed with the cross-correlation method. Combining the two-dimensional PIV analysis of horizontal and vertical planes, we were able to verify the time-averaged three-dimensional flow structures. In the forefront section, obvious differences were observed among the three cases. Specifically, in the normal case, the vertical vortex caused by the top flow and the transverse vortex caused by the side flow interacted with each other and created characteristic three-dimensional vortex structures in the region walled by spur dikes. Meanwhile, in the upstream and downstream-oriented cases, the flow structure was obviously different from that in the normal case. According to this, the orientation angle of spur dike was considered to affect on the water exchange significantly in this section. In the backward section, the flow deflection as seen in the forefront section was not observed. Furthermore, since averaged flow is relatively gentle, it was suggested that the turbulence transport plays an important role for the water exchange mechanism in the backward section.
Year: 2003