Determination of discharge capacity of rectangular side weirs using Schmidt approach

• The discharge capacity of rectangular side weir was investigated using the Schmidt approach.
• Schmidt, De Marchi and Domínguez approaches had similar tendencies for coefficient of discharge.
• It is sufficient to consider nappe heights in two point, as recommended by Schmidt.
• Schmidt approach was quite reliable for calculation of the discharge capacity.

Side weir is a hydraulic structure placed parallel to channel axis or angled to the channel wall in order to divert flow from a channel. Classical De Marchi hypothesis has commonly been used in previous studies to estimate discharge capacity of side weirs. In the present study, the discharge capacity of rectangular side weir was investigated using the Schmidt approach. Competence of average nape height as considered by Schmidt was examined via supplementary laboratory tests. 843 experimental runs were used in the study. In addition, to determine the reliability of the Schmidt approach for calculation of discharge capacity, obtained results were compared with De Marchi and Domínguez approaches. This study showed that Schmidt and Domínguez approaches had similar tendencies for coefficient of discharge, but the scatter data in the De Marchi approach was more significant. It is obvious that Schmidt approach was quite reliable for calculation of the discharge capacity.

A side weir is a hydraulic control structure used in irrigation and drainage systems and combined sewer systems. Classical De Marchi hypothesis has commonly been used in previous studies to estimate discharge capacity of side weirs. In the present study, the discharge capacity of rectangular side weir was investigated using the Schmidt. To determine the reliability of the Schmidt approach for calculation of discharge capacity, obtained results were compared with De Marchi and Domínguez approaches. The variation of the discharge coefficient with the Froude number has similar tendency for all approaches. However, the scatter data in the De Marchi approach is more significant and may lead to less reliable results.Figure optionsDownload as PowerPoint slide