Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 50 3 2018 08 23 Investigation of the Discharge Coefficient and Energy loss in a semi Cylindrical weir and semi Cylindrical Weir-gate Investigation of the Discharge Coefficient and Energy loss in a semi Cylindrical weir and semi Cylindrical Weir-gate 499 510 1989 10.22060/ceej.2017.10084.4824 FA F. Alizadeh Department of Water Engineering, Faculty of Agricultural Engineering, Sari agricultural sciences and natural resources University, Sari, Iran M. Saneie Soil Conservation and Watershed Management Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran M. Masoodian Department of Water Engineering, Faculty of Agricultural Engineering, Sari agricultural sciences and natural resources University, Sari, Iran Journal Article 2014 10 22 The present research investigate the discharge coefficient and energy loss flows of semi cylindrical wire- gate. The experiments were conducted in rectangular flume with the length of 8 m, width of 0.282 m and height of 0.3 m. In fact, the soil conservation and watershed management research that occurred in laboratory, used the physical models with diameters of 70, 120 and 160 mm in height of the opening between zero until radius and differently discharging. The ratio of cylindrical structure diameter to channel width (D/B) was included range of 0.25 to 0.57 and the Froude number was conducted range of 0.012 to 0.55. The research showed that all angles alignment structure discharge coefficient and dimensionless parameter Hf/H (the ratio of energy loss to the water depth upstream) cases curvature upstream and curvature of the downstream respectively with increasing dimensionless parameter H/P, increases and decreases. The constant a (H / P), discharge coefficient and dimensionless parameter Hf / H when the curvature is upstream semi cylindrical wire-gate due to the gradual shrinkage of flow lines and thus decrease the input is less than the curvature is downstream structure. The present research investigate the discharge coefficient and energy loss flows of semi cylindrical wire- gate. The experiments were conducted in rectangular flume with the length of 8 m, width of 0.282 m and height of 0.3 m. In fact, the soil conservation and watershed management research that occurred in laboratory, used the physical models with diameters of 70, 120 and 160 mm in height of the opening between zero until radius and differently discharging. The ratio of cylindrical structure diameter to channel width (D/B) was included range of 0.25 to 0.57 and the Froude number was conducted range of 0.012 to 0.55. The research showed that all angles alignment structure discharge coefficient and dimensionless parameter Hf/H (the ratio of energy loss to the water depth upstream) cases curvature upstream and curvature of the downstream respectively with increasing dimensionless parameter H/P, increases and decreases. The constant a (H / P), discharge coefficient and dimensionless parameter Hf / H when the curvature is upstream semi cylindrical wire-gate due to the gradual shrinkage of flow lines and thus decrease the input is less than the curvature is downstream structure. https://ceej.aut.ac.ir/article_1989_4a3e00961a08879c34f91ca0070ea2f5.pdf