Analysis of Piano Key Weir Drainage Characteristics

Abstract

The piano key weir is a new type of labyrinth weir structure form, its advantages such as stable structure, upstream and downstream inverted overhang and small base area greatly improve the scope of application, and it has high discharge capacity and overflow efficiency, which is considered as a very effective method to solve the shortage of reservoir and dam discharge flow, and has more applications abroad. In this paper, the experimental observation of the hydraulic characteristics of the discharge from the hydraulic physics model of the piano key weir confirms its good overflow capacity, but also limits the study of its complex flow. Combined with the numerical simulation software, the three-dimensional flow field of the piano key weir is numerically simulated based on the RNG k-ɛ turbulence model and the free-surface VOF technique to analyze the changes of hydraulic characteristics such as flow patterns, flow lines and flow velocities, and to clarify the hydraulic characteristics of the spillway and the mechanism of the improved spillway capacity by combining the experimental results of the physical model. In addition, a comparative analysis of the overflow capacity and flood discharge efficiency between the piano key weir and the traditional thin-walled weir is carried out to better reflect the advantages of the piano key weir in flood discharge by using the over-discharge ratio, and to discuss the application of the piano key weir in actual diseased reservoir and dam projects.