TY - JOUR T1 - An Experimental and Numerical Investigation at a 30 Degree Water Intake in Main Channel with Trapezoidal and Rectangular Section TT - مطالعه آزمایشگاهی و عددی الگوی جریان در آبگیر 30 درجه منشعب از کانال ذوزنقه‌ای JF - JSTNAR JO - JSTNAR VL - 15 IS - 57 UR - http://jstnar.iut.ac.ir/article-1-1859-en.html Y1 - 2011 SP - 35 EP - 46 KW - Lateral intakes KW - Diversion Stream width KW - Semi-trapezoidal channel KW - SSIIM2 model KW - Flow patterns. N2 - In diversion flows, a portion of stream flow which enters the intake is diverted from upstream of the intake denoted by a surface and is called dividing stream surface (DSS). The amount of flow and sediment discharge entering the intake as well as design of submerged vanes to control sediment depends on determination of dividing stream width. In this study, the experimental tests were carried out at a 30 degree water intake from a trapezoidal section. Three components of velocity data were obtained for different flow conditions. Then numerical SSIIM2 model was calibrated and verified using tests data. More flow conditions such as the main channel with rectangular section were run using SSIIM2 model to get enough hydraulic data. From analysis of these datas it was found that the dividing stream width in different distances from the bed depends directly upon the diversion flow ratio. It was found that in comparison to the rectangular section, in trapezoidal cross section, the DSS dimensions are modified in such a way that its width is increases at the surface and reduced at the bed for the same flow conditions. Relations for predicting the dividing stream width and diversion flow ratio have been presented in this paper for intake from both rectangular and trapezoidal cross sections. M3 ER -