The effect of submerged vanes on hydraulic properties of open channel flow

Submerged sill or vane is a small flow training structure, which has been widely used in some countries to prevent erosion from the outer bank of the rivers, sediment control diversion at water intakes and bridge crossing successfully. Although this technique has broad range of applications, but the potential of submerged vane technique as a control measure have not been fully explored. This paper summarizes the most significant effect of submerged vanes on hydraulic parameters such velocity, momentum, pressure, drag force, hydraulic gradient, energy gradient and flow regime of open channel flow. For this purpose, a series of laboratory tests were conducted for both with and without vanes conditions in the laboratory. The results showed that relative velocity, relative momentum and relative pressure profiles along the flume over vanes array were changing with the number of vanes. When the number of vanes increased from zero to five, the relative velocity and relative momentum increased and relative pressure reduced gradually over the vanes. The drag force inserted by vanes at lower water level was much greater than the higher water level. The hydraulic gradient reduced when the water depth ratio rose for a constant discharge. A small rise in vane height or drop in water depth would cause a high reduction in hydraulic gradient over the vanes array.

Keywords:

Drag , momentum , open channel , pressure , vane