Evaluation and sensitivity analysis of three-dimensional numerical simulation for aerated deflector-generated jets in spillways

• Published in: Water science & technology. Water supply Vol. 23; no. 1; pp. 114 - 128
• Main Authors: He, Junling, Yin, Jinbu, He, Hong, Ren, Panhong, Zhang, Shuguang, Du, Zhenkang
• Format: Journal Article
• Language: English
• Published: London IWA Publishing 01.01.2023
• Subjects: Aeration; Air; air concentration; Air-water interface; Bubbles; Cavitation; Cavitation erosion; clear-water length; Corrosion; Dimensions; Drag; Entrainment; Finite volume method; Fluid flow; Height; Hydraulic engineering; Jet flow; Mathematical models; multiphase flow; Numerical models; numerical simulation; Reynolds number; Roughness; Sensitivity analysis; Simulation; Spillways; the two-fluid model; Three dimensional analysis; Three dimensional models; Turbulence; Turbulence models; Two fluid models; Velocity; Viscosity; Water
• ISSN: 1606-9749; 1607-0798
• DOI: 10.2166/ws.2022.428

Abstract Aeration is an efficient way to prevent cavitation erosion of a discharge structure and alleviate damage to trajectory nappe on the downstream energy dissipator. Due to the complexity of the aeration jet, it is still a big challenge to understand the aeration mechanism at the water-air interface. This study applied the two-fluid model to simulate three-dimensional entrainment characteristics of jet flow, and also analyzed effects of bubble size, wall roughness, drag force model, turbulence model, and numerical model dimension on clear-water length. Results reveal that the two-fluid model can accurately and effectively simulate clear-water length, thickness variation, and average cross-section air concentration of jet flow with maximum error of 4.1%, 6.5% and 4.2% (x = L1, defining clear-water length with 1% air concentration as L1), respectively. Wall roughness height has a crucial influence on clear-water length. Taking L1 as an example, clear-water length decreases by 13.9% when roughness height increases from 0 to 3 mm. The drag models and bubble particle sizes affect clear-water length only when the profile aeration concentration is greater than 15%. Turbulence model and numerical model dimension have a minor effect on clear-water length.