The role of breakup and coalescence in fine-scale bubble-induced turbulence. II. Kinematics

This second part of our research explores the kinematic aspect fine-scale bubble-induced turbulence (BIT) to (i) present effect bubble breakup and coalescence (ii) compare it against universal characteristics reported in literature. To this end, we simulate a dilute bubbly system 0.5% void fraction using two distinct numerical simulations. In volume-of-fluid (VoF) simulation, bubbles undergo coalescence. immersed boundary method (IBM) however, they act as rigid spheres. We also perform simulation classical homogeneous isotropic (HIT). The first important outcome study is that BIT radically different from HIT terms its characteristics. vorticity-dominating regions, exhibits weak vortex stretching. stretching due (a) intermediate strain-rate eigenvalues skewed weakly positive (b) extensive eigenvector aligning perpendicular vorticity vector. has, on average, not only enstrophy production but strain strain-dominating regions. presence highly strained fluid elements absolute magnitude compressive eigenvalue being close eigenvalue. Thus, none noted for BIT. conclusion play little no influence kinematics VoF IBM simulations produce similar results.