TY - JOUR ID - 3774 TI - Determination of Discharge Coefficient in Ogee Spillways and Investigation the Effects of Submergence, Upstream Slope and Apron Elevation on Its Variations JO - Amirkabir Journal of Civil Engineering JA - CEEJ LA - en SN - 2588-297X AU - Heidary, Parvaneh AU - Salmasi, Farzin AU - Arvanaghi, Hadi AD - University of Tabriz, Tabriz, Iran AD - AD - Associated Professor, Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz-Iran Y1 - 2021 PY - 2021 VL - 53 IS - 7 SP - 2715 EP - 2734 KW - Ogee spillway KW - Discharge Coefficient KW - upstream slope KW - downstream apron elevation KW - free and submerged flow DO - 10.22060/ceej.2020.17257.6503 N2 - Discharge over the ogee spillway is related to the length of crest, upstream total head, and discharge coefficient. Also, the discharge coefficient is influenced by several factors. In this study, some parameters that are affecting the discharge coefficient in ogee weir are investigated. These are ogee spillway upstream slope, apron elevation, and downstream submergence. In this regard, some ogee spillway physical models were fabricated. These models include (1) ogee spillway with vertical upstream face, (2) ogee spillway with inclined upstream face (18, 33, and 45 degrees), (3) ogee spillways with downstream apron elevations (3, 5, 7, and 10 cm thickness) in free flow, and (4) ogee spillway with the vertical upstream slope in submerged flow condition. Results showed that in all the ogee weirs, the discharge coefficient (C) increases with increasing (P/He) and then remain constant. The value of the discharge coefficient decreased from 2.25 (in free flow) to 2.15 (in submerged flow). For a constant value of head over ogee spillways (He), the discharge coefficient decreased with increasing downstream apron elevation and submergence. The relative discharge coefficient had a constant trend at the beginning with parameter (hd/He), then it had a decreasing trend. The threshold value for submergence (hd/He), was 0.75 in the ogee spillway in this study. With increasing relative submergence (hd/He) from 0.75 to 1, the relative discharge coefficient (Cs/C0) decreased from 0.88 to 0.24.   UR - https://ceej.aut.ac.ir/article_3774.html L1 - https://ceej.aut.ac.ir/article_3774_95408d752b2ee2098f8af3777ee3ae5c.pdf ER -