Experimental Investigation of Flow Past Submerged Vanes

In this paper the physics of the flow past a submerged vane at high angles of attack is presented. The data presented were collected during an experimental study of flow past vanes at various angles of attacks in a deformable-bed straight rectangular channel. The first few experimental runs were undertaken to establish the optimal angle of attack required to generate the strongest secondary circulation in the flow. At this optimal angle of attack, the flow features responsible for the transverse movement of bed sediment are clearly identified. The differences between the flow features observed near the vanes at both low and high angles of attack, are also outlined. These include, among others, two counterrotating vortices for vanes at high angles of attack as opposed to the widely acclaimed hypothesis of a single vortex for low angles of attack.