Physical and Numerical Modeling of the Hydraulic Characteristics of Type-A Piano Key Weirs

Abstract

Piano key weirs (PKWs) have been introduced in recent years as a hydraulically efficient and cost-effective type of spillway, and there are more than 30 PKWs under construction or already constructed globally. However, owing to the numerous geometric parameters and complex hydraulic characteristics of PKWs, the discharge capacity of a PKW is still difficult to estimate. To improve the overall understanding of the flow behavior in the vicinity of PKWs and to investigate the intrinsic link between the structural parameters and discharge capacity of PKWs, this study employs a combination of numerical simulations and physical model tests to investigate the hydraulic characteristics of PKW models (including flow regimes, water surface lines, streamlines, and flow velocities) under different water head conditions. Furthermore, based on the detailed flow field information provided by the numerical simulations, the internal mechanism for the discharge capacity of the PKW is revealed by analyzing the flow field under the weir crest and the distribution of turbulent kinetic energy near the PKW.