Author(s): M. R. Pirestani; M. R. M. Tabatabai; N. Barkhordari; S. P. Jazayeri
Linked Author(s):
Keywords: Bend channel; Lateral intake; Flow strength; Momentum
Abstract: River is a dynamic system in which morphological changes occur continuously. Therefore, these variations have to be investigated to predict river behaviour. For river diversions, flow characteristics, sediment transport conditions and hydraulic geometry of stream have to be considered. Furthermore, flow diversion is hydraulically three dimensional and non-uniform. Flow in river bends is three-dimensional and non-uniform in which a helicoidal flow is generated from secondary flow and the main stream flow interaction. With regards to flow pattern in river bends, which is proportional to helicoidal flow strength, and sediment characteristics, erosion and sedimentation occur in the river bed. As a result, locations of river structures such as intakes are of importance. In order to monitor variations of velocity and secondary flow strength caused by the changes of flow hydraulic parameters in the vicinity of lateral intakes in bend channel, a U-shape rectangular cross-section channel with fixed bed was designed and made. A straight channel with rectangular section was used as diversion channel. Based upon past researches, diversion angle was selected 60? in different intake locations (40, 75 and 115) with Froud numbers variations (0. 27, 0. 41 and0. 55). By using data for each experiment, the flow strength and momentum variations were analysed to observe the influence of the intake location and flow regime on flow-pattern in the vicinity of the lateral intake. Moreover, the most variations of flow strength and momentum were occurred downstream of entrance of the lateral intake.
Year: 2010