2025 Volume 81 Issue 16 Article ID: 24-16141
In this study, the characteristics of the flow field in an open channel in which a longitudinal ridge element with a suction function was installed on the bottom wall, with the suction operation in the upstream half region was examined. Regarding the pronounced upward flow and paired swirling flow that disappear with full-area suction operation, when the upstream half region operation is performed, the formation of upward flow remains at the half-water depth position, and the paired swirling flow disappears. It was also observed that the Reynolds shear stress (-uv) in the vertical direction was relatively small compared to the case without suction operation and with suction in all areas. Additionally, the distribution of the turbulence energy generation term (-uv(dU/dy) was found to be relatively small compared to the case of no suction operation and all area suction operation. These characteristics are thought to be due to the undeveloped longitudinal vortex structure formed downstream of the upstream half region.
