Scalings and decay of homogeneous, nearly isotropic turbulence behind a jet array

Tan, Shiyong; Xu, Xu; Qi, Yanyuan; Ni, Rui

doi:10.1103/physrevfluids.8.024603

Cited by 6 publications

(1 citation statement)

References 51 publications

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“…The bubbles were injected directly into the test section via a needle with inner diameter 5 mm, and the air was supplied by a stainless steel gas line (represented by the grey line in figure 1a). The tip of the needle is located at around 6 times the nozzle-to-nozzle separation distance above the jay array, where jets are fully mixed and the generated turbulence becomes homogeneous and isotropic as suggested by Tan et al (2023). By carefully adjusting the gas flow rate using a syringe pump, a single bubble with diameter ranging from 7 to 13 mm was generated in each run in order to avoid large bubble clusters generated from breakups blocking camera views.…”

Section: Discussionmentioning

confidence: 99%

Breaking bubbles across multiple time scales in turbulence

Qi,

Xu,

Tan

et al. 2024

J. Fluid Mech.

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The familiar process of bubbles generated via breaking waves in the ocean is foundational to many natural and industrial applications. In this process, large pockets of entrained gas are successively fragmented by the ambient turbulence into smaller and smaller bubbles. The key question is how long it takes for the bubbles to reach terminal sizes for a given system. Despite decades of effort, the reported breakup time from multiple experiments differs significantly. Here, to reconcile those results, rather than focusing on one scale, we measure multiple time scales associated with the process through a unique experiment that resolves bubbles’ local deformation and curvature. The results emphasize that the scale separation among various time scales is controlled by the Weber number, similar to how the Reynolds number determines the scale separation in single-phase turbulence, but shows a distinct transition at a critical Weber number.

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Section: Discussionmentioning

confidence: 99%