Analysis of Flow Dynamics and Energy Dissipation in Piano Key and Labyrinth Weirs Using Computational Fluid Dynamics

Abstract

This chapter investigates the flow dynamics and energy dissipation of Piano Key Weirs (PKWs) and Labyrinth Weirs (LWs) using Computational Fluid Dynamics (CFD) models. PKWs and LWs are nonlinear weirs designed to enhance discharge capacity and energy dissipation in reservoirs and flood control facilities. Our research employs the FLOW-3D and ANSYS models to analyze various geometric parameters and their effects on discharge performance and energy dissipation. For PKWs, the analysis indicates that trapezoidal PKWs outperform rectangular PKWs regarding discharge efficiency due to their larger inlet flow area and improved flow distribution. Additionally, moving the PKW overhangs toward upstream-zone enhances discharge performance, while moving them toward downstream zone increases energy dissipation. For LWs, the analysis demonstrated that LWs with smaller sidewall angles increase crest length, enhancing discharge performance but leading to early submergence, decreasing the energy dissipation. Finally, it concludes that PKWs and trapezoidal LWs have a new function as structures that dissipate energy near the maximum limit. The findings confirmed the ability of the FLOW-3D and ANSYS models to accurately predict the various flow characteristics. It also provides valuable insights for designing and optimizing PKWs and LWs to balance discharge efficiency and energy dissipation, ensuring the safety and resilience of flood control structures.