Flow Structure and Sediment Motion around Submerged Vanes in Open Channel

The use of submerged vanes to divert sediment movements on seabed and open channel flows are common in many engineering projects. In the present study, experiments were conducted to investigate the characteristics of flow and sediment motion around a submerged vane in a large flume, 30m long, 6m wide, and 0.6m high, paved with lightweight cylindrical plastic material with specific gravity of 1.05. The size of the uniform plastic material is 2.8mm in diameter and 3.1mm in height. The vane was made of 10mm thick steel plate. The height of the vane above the mean bed ranged from one-eighth to one-third of the flow depth and its length is between 1to4m. The alignment of the vane to the approach flow varied from 15° to 90°. The effectiveness of the submerged vane in sediment diversion depends on the vane alignment to the approach flow, and the height and length of the vane. The optimum skew angle to the approach flow for the purpose of sediment diversion is about 30°. The optimum vane height of two to three times the height of the bedform would be able to resist the bedload “escaping” over the bedform crest.