Unresolved behavior of Rayleigh–Bénard convection beyond the classical high-Rayleigh-number regime

Characterize the important unresolved physical questions in Rayleigh–Bénard convection beyond the classical regime of very large Rayleigh numbers of 10^11 or more.

Background

Rayleigh–Bénard convection is used as an idealized model for buoyancy-driven turbulent flows and is governed primarily by the Rayleigh and Prandtl numbers. The paper notes that direct numerical simulation becomes increasingly expensive as the Rayleigh number grows because progressively finer spatial scales must be resolved.

Against this computational background, the authors identify the physical behavior of Rayleigh–Bénard convection beyond the classical regime at Rayleigh numbers of approximately 10^11 or higher as an area containing important unresolved questions. The paper does not specify the individual questions, but situates them in the extreme-Rayleigh-number regime that motivates the need for more capable simulation methods.