نوع مقاله : مقاله پژوهشی
نویسندگان
1 کارشناس گروه مهندسی آب دانشگاه علوم کشاورزی و منابع طبیعی ساری
2 دانشیار گروه مهندسی آب، دانشگاه علوم کشاورزی و منابع طبیعی گرگان
3 دانشیار گروه مهندسی آب، دانشگاه علوم کشاورزی و منابع طبیعی ساری
4 دانشیار گروه مهندسی آب، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Flow control and measurement structures such as gates and weirs are important components in irrigation and drainage networks. With regard to the problem of sedimentation in weirs and the accumulation of floating materials behind the gates, a combined weir- gate structure to facilitate draining of materials through the gate and suspended materials through weir. One of its types is half-cylindrical weir–gate which, due to the curvature of the flow lines and adhesion on body of the structure, it has advantages including ease of passage of floating objects, ease of design, higher flow discharge coefficient compared with other combined structures (sharp-crested and broad-crested, etc.). This research was aimed to analyze the hydraulic of passing flow from half-cylindrical weir–gate structure by rotating around the center and edges half-cylindrical from 0° to 180° with fixed gate opening height. Experiments were done in a rectangular and horizontal flume with 11 meter length and 30cm width under three models of half-cylindrical weir–gate with 70, 120 and 160 mm diameters. The minimum discharge coefficient occurred at 90° and its maximum happened at 45° and 30° angles, respectively. For diameters of 70, 120 and 160 mm, the minimum back water was observed at 0°, 45° and 30°, respectively, and the largest one was observed at 90° for all three diameters. Moreover, in relation to the depth of upstream water to the opening of the fixed valve, for the angles, by increasing diameter, the discharge coefficient of the combined structure decreased. The results showed that, in addition to the angle of the half-cylindrical curvature relative to horizon line, the diameter of the structure is effective on the discharge coefficient and back water of the combined structure.
کلیدواژهها [English]