Numerical validation of novel scaling laws for air entrainment in water

Catucci, Daniele; Briganti, Riccardo; Heller, Valentin

Abstract

The Froude scaling laws have been used to model a wide range of water flows at reduced size for almost a century. In such Froude scale models, significant scale effects for air-water flows (e.g. hydraulic jumps or wave breaking) are typically observed. This study introduces novel scaling laws, excluding scale effects in the modelling of air-water flows. This is achieved by deriving the conditions under which the governing equations are self-similar. The one-parameter Lie group of point-scaling transformations is applied to the Reynolds-averaged Navier-Stokes equations, including surface tension effects. The scaling relationships between variables are derived for the flow variables, fluid properties and initial and boundary conditions. Numerical simulations are conducted to validate the novel scaling laws for (i) a dam break flow interacting with an obstacle and (ii) a vertical plunging water jet. Results for flow variables, void fraction and turbulent kinetic energy are shown to be self-similar at different scales, i.e. they collapse in dimensionless form. Moreover, these results are compared with those obtained using the traditional Froude scaling laws, showing significant scale effects. The novel scaling laws are a more universal and flexible alternative with a genuine potential to improve laboratory modelling of air-water flows.

Citation

Catucci, D., Briganti, R., & Heller, V. (2021). Numerical validation of novel scaling laws for air entrainment in water. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 477(2255), Article 20210339. https://doi.org/10.1098/rspa.2021.0339

• Journal Article Type: Article
• Acceptance Date: Oct 6, 2021
• Online Publication Date: Nov 3, 2021
• Publication Date: Nov 24, 2021
• Deposit Date: Oct 14, 2021
• Publicly Available Date: Oct 14, 2021
• Journal: Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
• Print ISSN: 1364-5021
• Electronic ISSN: 1471-2946
• Publisher: The Royal Society
• Peer Reviewed: Peer Reviewed
• Volume: 477
• Issue: 2255
• Article Number: 20210339
• DOI: https://doi.org/10.1098/rspa.2021.0339
• Keywords: General Physics and Astronomy; General Engineering; General Mathematics
• Public URL: https://nottingham-repository.worktribe.com/output/6459024
• Publisher URL: https://royalsocietypublishing.org/doi/10.1098/rspa.2021.0339