Performance evaluation of aspect ratio of submerged vanes

Submerged vanes are submerged foils of low height (H) and higher length (L) structures, which are constructed in river at an angle of attack to the fl ow to modify the near-bed fl ow pattern and redistribute fl ow and sediment transport within the channel cross-section. The aspect ratio of submerged vane is defi ned as H/L. The aspect ratio of submerged vane is one of the most important parameters which infl uences the generation of strength of vane induced secondary circulation. At 2.5H downstream of vane, dimensionless moment of momentum MOM*, MOM**, MOM*** increase with the reduction in aspect ratios of submerged vane. The strength of vortex induced by vane among three values of aspect ratios such as 0.25, 0.33 and 0.50, is maximum at lowest aspect ratio 0.25. At lowest aspect ratio, the maximum value of vane-induced strength of vortex led to the increased deposition of sediments (dike). Generation of vortex starts right from the leading edge and it is amplifi ed till it reaches the trailing edge of submerged vane due to increase in vane length.