Scienceline Publications Journal of Civil Engineering and Urbanism 2252-0430 6 3 2016 May Variations of Flow Separation Zone at Lateral Intakes Entrance using Submerged Vanes 54 63 http://www.ojceu.ir/main/attachments/article/52/J.%20Civil%20Eng.%20Urban.,%206%20(3)%2054-63,%202016.pdf EN Azade Jamshidi Graduate Student of Hydraulic Structures, Department of Water engineering, Agricultural Faculty, Tabriz University, Tabriz, Iran. Davood Farsadizadeh Professor, Department of Water Engineering, Faculty of Agriculture, Tabriz University, Tabriz, Iran. Ali Hosseinzadeh Dalir none of address Flow Separation in the upstream of the intake channel is a critical issue causing eddy flow into the intake entrance. It reduces the intake efficiency and the effective width of flow in intake. Therefore, it is essential to identify the dimensions of the flow separation zone. Installation of submerged vanes in intake entrance is a method which is usually applied to reduce the size of flow separation zone. In this study the dimensions of flow separation zone were measured in presence of submerged vanes with five arrangements including parallel, stagger, compound, piney and butterflies (the piney and butterflies models were provided for the first time that is our innovation in present paper ) by four discharges of 15, 20, 25 and 30 L/s in main channel entrance. Multivariate regression equations were extracted for investigated flow separation zone using SPSS software. R2 of these equations changes from 0.87 to 0.96, which statistically, can be considered as valid equations in hydraulic flow studies at lateral intake entrance. These results are also comparable with other studies which all of them show a reducing of the size of flow separation zone with increasing ratio of lateral intake discharge. Piney submerged vanes were selected as the best model that reduced the size of flow separation zone and made proper flow profile in main channel and intake entrance. Comparing with pilot model tests, this model reduced the length and width of flow separation zone 36.34%, 32.53%, 34.37%, 30.72% and 27.46%, 31% , 31.33 % , 30% respectively at four different discharges of 15, 20, 25 and 30 L/s. Results showed that the ratio of width to length of separation zone (shape index of zone) was between two values 0.2 and 0.28 in the all models. Intake channel Flow separation zone Submerged vanes Shape index of zone Piney model