Bubbly and Buoyant Particle-Laden Turbulent Flows

TL;DR

This review synthesizes current understanding of bubbly and buoyant particle-laden turbulent flows, highlighting different dynamical regimes, flow modifications, and future research directions in natural and industrial contexts.

Contribution

It provides a comprehensive summary of phenomenological aspects, regimes, and flow modifications caused by bubbles and buoyant particles in turbulence, based on recent experiments and simulations.

Findings

Different dynamical regimes identified, including crossing trajectories and wake oscillations.

Bubbles and particles influence flow structures and wall accumulation.

Flow modifications depend on turbulence type and particle properties.

Abstract

Fluid turbulence is commonly associated with stronger drag, greater heat transfer, and more efficient mixing than in laminar flows. In many natural and industrial settings, turbulent liquid flows contain suspensions of dispersed bubbles and light particles. Recently, much attention has been devoted to understanding the behavior and underlying physics of such flows by use of both experiments and high-resolution direct numerical simulations. This review summarizes our present understanding of various phenomenological aspects of bubbly and buoyant particle-laden turbulent flows. We begin by discussing different dynamical regimes, including those of crossing trajectories and wake-induced oscillations of rising particles, and regimes in which bubbles and particles preferentially accumulate near walls or within vortical structures. We then address how certain paradigmatic turbulent flows, such as homogeneous isotropic turbulence, channel flow, Taylor-Couette turbulence, and thermally driven turbulence, are modified by the presence of these dispersed bubbles and buoyant particles. We end with a list of summary points and future research questions.