Air entrainment and splash characteristics in jet flows: Effect of downstream water levels

Abstract

This study investigates the air–water interaction dynamics in jet streams, with particular emphasis on the transition from the cavity to the far-field regions. A dual-tip conductivity phase-detection probe was employed to analyze four distinct downstream water levels. Based on the development of the cross-sectional mean air concentration, the jet flow was divided into four distinct regions: the jet length region, impact region, splash region, and far-field region. The results demonstrate varying trends in the evolution of the mean air concentration and maximum bubble frequency. Downstream water levels exerted a significant influence on these parameters in the splash and far-field regions, whereas minimal variation was observed in the impact region. Additionally, notable differences were identified in the probability density function of water droplets between the cavity and downstream regions. Furthermore, downstream water depth was found to have a negligible effect on the proportion of small-sized droplets in both the impact and splash regions.

Keywords

air entrainment / bubble count / jet flow / water droplet

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RIGHTS & PERMISSIONS

2025 The Author(s). River published by Wiley-VCH GmbH on behalf of China Institute of Water Resources and Hydropower Research (IWHR).