Dynamics of dispersed bubbly flow over a lifting surface: Gas diffusion and bubble breakup effects. (1st October 2020)

• Record Type: Journal Article
• Authors: Hsiao, Chao-Tsung; Chahine, Georges L.; Ma, Jingsen
• Is Part Of: Ocean engineering. Volume 213(2020)
• Publication Date: 2020-10-01
• Subjects: Bubbly flow -- Gas diffusion -- Bubble breakup -- Cavitation -- Eulerian-Lagrangian approach; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2020.107630
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: The modification of the bubble nuclei population by the presence of a finite-span hydrofoil is modeled numerically using an Eulerian-Lagrangian approach. The unsteady liquid flow field is simulated using Navier-Stokes equations, while the bubbles, initiating from nuclei in the free stream and emitted from boundaries, are tracked using a Lagrangian approach. The effects of including gas diffusion, wall nucleation, and bubble breakup on nuclei distribution downstream of hydrofoil are studied. The inclusion of gas diffusion is found to significantly increase the size of the bubbles downstream. Also, inclusion of boundary nucleation is found to significantly increase the total number of large bubbles collected in the wake as compared to accounting for free nuclei alone. Bubble breakup, modeled using instability analysis and experimental observations, is seen to result in a significant increase in the number of small and mid-size bubbles, at the expense of the large size bubbles. Highlights: Long-lasting bubbles observed in the wake is attributed to rectified gas diffusion. Water containing more nuclei resulted in higher total volume of gas bubbles downstream. Two breakup models, based on analytical and empirical approaches, were developed. Analytical breakup model resulted in a larger number of fine bubbles in the wake.