FL49CH06-Boffetta ARI 8 June 2016 13:57 V I E E W R S I E N C N A D V A Incompressible Rayleigh–Taylor Turbulence Guido Boffetta1,2 and Andrea Mazzino3,4,5 1Department of Physics, University of Torino, Torino 10125, Italy; email:
[email protected] 2INFN, Section of Torino, Torino 10125, Italy 3Department of Civil, Chemical, and Environmental Engineering, University of Genova, Genova 16145, Italy; email:
[email protected] 4CINFAI, Section of Genova, Genova 16145, Italy 5INFN, Section of Genova, Genova 16146, Italy Annu. Rev. Fluid Mech. 2017. 49:119–43 Keywords The Annual Review of Fluid Mechanics is online at turbulent convection, mixing, heat and mass transfer, complex flows fluid.annualreviews.org This article’s doi: Abstract 10.1146/annurev-fluid-010816-060111 Basic fluid equations are the main ingredient in the development of theories Copyright c 2017 by Annual Reviews. of Rayleigh–Taylor buoyancy-induced instability. Turbulence arises in the All rights reserved late stage of the instability evolution as a result of the proliferation of active scales of motion. Fluctuations are maintained by the unceasing conversion of potential energy into kinetic energy. Although the dynamics of turbulent fluctuations is ruled by the same equations controlling the Rayleigh–Taylor instability, here only phenomenological theories are currently available. The present review provides an overview of the most relevant (and often contrast- ing) theoretical approaches to Rayleigh–Taylor turbulence together with numerical and experimental evidence for their support. Although the focus is mainly on the classical Boussinesq Rayleigh–Taylor turbulence of miscible fluids, the review extends to other fluid systems with viscoelastic behavior, affected by rotation of the reference frame, and, finally, in the presence of reactions.