Discharge Coefficient of the Pivot Weir: A Review
Arwa A. Mala Obaida
Department of Dams and Water Resources Engineering, College of Engineering, University of Mosul, Mosul, Iraq.
Azza N. Altalib *
Department of Dams and Water Resources Engineering, College of Engineering, University of Mosul, Mosul, Iraq.
*Author to whom correspondence should be addressed.
Abstract
Weirs are one of the structures that are used for flow measurements. A pivot weir is one of these structures. It may be defined as a thin rectangular plate that tilts at different angles from the vertical axis placed in the middle of the channel. The current study was conducted to identify the studies that used this type of weir to discharge coefficient investigation. The results referred to reducing discharge coefficient in lateral contractions and increases as the weir inclination angle increases. Research has also demonstrated that the discharge coefficient is lower when two neighbouring weirs are used with the same inclination angle than when they are used with different angles. The results also show that the shape of the crest of the semi-circular pivot weir increases the value of the coefficient of discharge compared to the shape of the sharp and circular crest.
Keywords: Pivot weirs, angle of inclination, inclined weir length, coefficient of discharge