Experimental and Simulation Studies on Water Discharge Coefficients of Rectangular Piano Key Weirs

Abstract

The piano key weir (PKW) is a developed type of labyrinth spillway with the ability to transfer large amounts of discharge by keeping executive costs constant. In this study, the parameters affecting the discharge coefficient of nine models were evaluated using physical models and simulations by Flow-3D software. The PKW models included: PK1.0, PK1.1, PK1.2, PK1.3, PK1.4, PK1.5, and PK1.6 representing the width ratios of the inlet (Wi) to outlet (Wo) keys of 1.0, 1.1, 1.2, 1.3, 1.4, 1.5 and 1.6 respectively and the other two models were PKT (PK1.1 with a thicker wall) and PKTP (PK1.1 with a thicker wall and an enhanced crown). According to the results of experimental and simulation evaluations, the model of PK1.4 was selected as the optimal model, which increased the discharge rate by 30% compared to the control weir. Moreover, increasing wall thickness (PKT model) led to an increase in the discharge and installing a parapet wall (PKTP model) resulted in an increase in discharge and a uniform distribution of flow lines on the weir. Considering the superiority of models PK1.4, PKT, and PKTP, the geometric properties of these models can be used to optimize the design of PKWs.

Keywords

• flow-3d
• overflow
• parapet wall
• physical models
• piano key weir
• water flow