The Study of the Effect of the Sill Slope on the Discharge Coefficient of the Labyrinth Weir

The discharge coefficient of the labyrinth weirs is influenced by geometric factors and flow characteristics. In this study, the effect of the sill slope that is a geometric factor on the discharge coefficient of the labyrinth weirs has been studied. The physical model is used for this purpose. In this regard, nine weir models were made with two cycles, and wall thickness of 3 cm, a quadrant shape crest, the heights of 10, 15, 20 centimeters and with sill slopes of 0%, 13%, 25%, 37%, and experimented in a laboratory flume with length of 9 meters, a bed width of 60 cm, and a wall height of 70 cm. Experiments were performed in a wide range of flow and discharge between 1 to 150 lps. The results indicated that the sill slope has a significant effect on the discharge coefficient of the labyrinth weir. In general, the weir performance will increase as the sill slope increases. So the sill slope of 25% appeared to be the optimum slope