Author(s): A. B. M. Faruquzzaman Bhuiyan; Richard Hey
Linked Author(s):
Keywords: Weir; Numerical modeling; 3d Flow pattern; Habitat enhancement
Abstract: Weirs are constructed in rivers to modify the instream flow characteristics. A clear understanding of their effects on flow by different layouts of the structure is necessary to achieve desired results. Numerical simulations and laboratory experiments have been carried out to compare flow structures with linear and folded weirs. Laboratory experiments were conducted in straight and meandering channels. A three-dimensional finite volume model has been verified and applied for numerical modeling. A good agreement is observed with the simulated flow patterns and the laboratory measurements. The generation of secondary flow and large-scale 3d flow structures have been compared in the selected cases. The results clearly show the sensitivity of the flow pattern with changes in layout. The secondary flow strength and bed shear stress are enhanced significantly by folded weirs with sloping crest. They induce multiple vortices in the downstream channel and demonstrate the scope of further manipulating the flow by changing the crest parameters in complex natural layout of channels including rivers with large sediment transport. Finally, the present results give insight about the internal flow structures downstream of the folded weirs that would guide their design as flow controlling, grade control and habitat enhancement device.
Year: 2005