2023/12/16 by Ron Shnapp, Shnapp, Ron, Markus Holzner +1
Earth and Planetary Sciences · Engineering · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Mixing #Lattice Boltzmann Simulation Studies #Oceanographic and Atmospheric Processes
paper · pdf · doi:10.48550/arxiv.2312.10363
openalex publication_date 2023/12/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Buoyancy-driven bubbly flows play pivotal roles in various scenarios, such as the oxygenation and mixing in the upper ocean and the reaction kinetics in chemical and bio-reactors. This work focuses on the convective flow induced by the localized release of large air bubbles (Db=3.7 mm, Reb=950) in a water tank, exploring the resulting flow and the transition from laminar to disturbed states as a function of the Rayleigh number in the range 3×103 ÷2×105. At low Ra the flow is smooth and laminar with weak temporal oscillations, while a highly disturbed state appears above a critical value Rac. A theoretical analysis is presented that links the mean flow circulation to the Rayleigh number. Through an experimental investigation, utilizing 3D-particle tracking velocimetry and flow visualization, we confirm the theory presented, and characterize the laminar to disturbed transition in the system. The study offers insights into the convective flow dynamics generated by bubbles, with implications for applications such as bio-reactor soft mixer design.