Determination of discharge capacity of side weirs using Schmidt method

The names of the weirs which are designed as parallel or with an angle to the axis of the channel and used in order to reduce the flow rate of a channel or decrease the level of water are side weirs. Side weirs have been used so as not to overflow the water transmission channels as a result of heavy rains or sudden snow melting and to sustain the desired amount of flow in the channels as a result of discharge of rain water in the drains. In this study, the discharge coefficients of the classic rectangular side weirs, triangular labyrinth side weirs and trapezoidal labyrinth side weirs have been determined by using the Schmidt method. This study has an originality because in literature there aren't any studies using the experiment results of the side weirs with this method. This study has been prepared using the data obtained model experiment sets of the rectangular, triangular labyrinth and trapezoidal labyrinth side weirs in laboratory. For the rectangular side weirs 835 experiment data, for the trapezoidal labyrinth side weirs 675 experiment data and for the triangular labyrinth side weirs 2623 experiment data have been used. Weir length for rectangular side weirs has been taken and calculated as 0.15, 0.25, 0.50, 0.75 and 1.50 m and weir length for triangular and trapezoidal side weirs has been taken and calculated as 0.25, 0.50 and 0.75 m weir height for all side weirs has been taken and calculated as 0.12, 0.16 and 0.20 m. In this study, the data that obtained from the experiment model has been used in order to determine the exchange of discharge coefficient both considering the Froude number and dimensionless weir crest elevation. The discharge coefficient has been calculated with Schmidt method in two ways. In the first method , downstream weir crest elevation and upstream weir crest elevation have been considered and with the average of these two point C_d has been calculated. In the second method, the average water heights of three points; downstream weir crest elevation, middle of the channel and upstream weir crest, have been taken and calculated *C_d. It has been observed that the tendencies of the Schmidt method and De Marchi method are compatible and it has been understood that side weir discharge coefficient can be determined easily by using Schmidt method. Keywords: Rectangular side weir, Triangular labyrinth side weir, Trapezoidal labyrinth side weir, Schmidt approach.