A robust and accurate technique for Lagrangian tracking of bubbles and detecting fragmentation and coalescence

Bubble production by air filament and cavity breakup in plunging breaking wave crests

“…The extracted cylinder, shown in figure 4( b ), contains small bubbles that affect the data analysis, which are identified and removed using the bubble identification algorithm developed by Herrmann (2010) and recently employed by Gao et al. (2021). The result is shown in figure 4( c ), which contains only the cylinder of interest.…”

“…( c ) Small bubbles are removed leaving only the air cylinder using a bubble identification algorithm (Herrmann 2010; Gao et al. 2021). ( d ) Equivalent cross-sectional radius as a function of spanwise direction (solid line) and a characteristic radius (dashed line).…”

“…(2017), Yang, Deng & Shen (2018) and Gao et al. (2021). A third-order Stokes wave with a large initial steepness in a periodic domain (Chen et al.…”

“…The simulations are performed by solving the incompressible Navier-Stokes equations on a fixed Eulerian grid, where the air-water system is treated as a coherent system with varying physical properties. The in-house code used here implements the CLSVOF method (Sussman & Puckett 2000) in capturing the air-water interface and is described in detail in Hu et al (2012), Liu (2013), Yang et al (2017), Tang et al (2017), Yang, Deng & Shen (2018) and Gao et al (2021). A third-order Stokes wave with a large initial steepness in a periodic domain (Chen et al 1999;Iafrati 2009;Deike et al 2016;Wang et al 2016;Tang et al 2017;Yang et al 2017Yang et al , 2018) is adopted here.…”

“…Grid convergence of simulation results Available computational resources limit the grid resolution of the breaking wave simulations for a wave of length 25 cm, which is typically considered in simulation studies, to approximately 0.3 mm, which is not small enough to accurately capture surface tension physics of the smallest bubbles of interest (e.g. Deike et al 2016;Wang et al 2016;Gao et al 2021). Three convergence studies were conducted to ensure that the simulated breaking wave bubble size spectrum and the wavenumbers of the most unstable mode of simulated air cylinders were not impacted by grid resolution.…”