Bubbly and Buoyant Particle–Laden Turbulent Flows

Abstract

arXiv:2005.13774v1 [physics.flu-dyn] 28 May 2020

Life and death of inertial particle clusters in turbulence

“…Also, light bubbles are known to produce even more concentrated and long-lived clusters (Tagawa et al. 2012; Mathai, Lohse & Sun 2020), and, therefore, the present methodology is expected to provide similar insight into bubble-laden turbulence. In general, the approach can be applied to any system of clustering elements that can be tracked in a Lagrangian framework.…”

Hydrodynamic forces on a clean spherical bubble translating in a wall-bounded linear shear flow

“…Fits (23) and (24) may be used to predict the wall-induced drag correction and transverse force in a fluid at rest, respectively. Similarly, fits (30) and (33) and (34), which reduce to the former set for Sr = 0, apply in wall-bounded shear flows irrespective of the sign of the shear rate and relative fluid-bubble velocity. These models represent a significant improvement over current "point-particle" models of spherical bubbles which do not account for any wall-induced effect but are nevertheless routinely used to simulate laminar and turbulent wall-bounded bubbly flows.…”

“…The results provided in this paper may have an important bearing on the numerical prediction of wall-bounded bubbly flows, especially because they are of direct use to improve the socalled "point-particle" models in which wall effects are usually ignored. Such improved models for bubble Lagrangian tracking may then be used to investigate situations as diverse as turbulent wallbounded bubbly flows [30], bubbly flows in vertical pipes and channels [31][32][33][34], drag reduction or enhancement by microbubbles in turbulent boundary layers [35][36][37][38][39][40], or lateral migration of bubbles in wall-bounded shear flows [41].…”

Non-monotonic transport mechanisms in vertical natural convection with dispersed light droplets

“…Within a liquid, they can play an important role in the transport of mass and heat. Such complex interactions of bubbles and liquids can be found in various applications and process technologies, for example in cooling systems of power plants, metallurgical industries, catalytic reactions and in the mixing of chemicals (Brennen 2005; Balachandar & Eaton 2010; Mathai, Lohse & Sun 2020). One commonly studied class of bubble–liquid interaction is the bubble column (Mudde 2005), where liquid turbulence is generated and sustained by a rising swarm of bubbles.…”