Toward DNS of the Ultimate Regime of Rayleigh–Bénard Convection

Sheared Rayleigh-Bénard turbulence

“…Unfortunately, temperature is relatively inefficient to enhance momentum and boundary layers transition to turbulence only for very high values of the forcing that has been achieved only in few experiments [46] and recently in two-dimensional numerical simulations [108]. On the other hand, despite the considerable effort and the progress of nowadays computers, this ultimate regime is still out of reach of three-dimensional numerical simulation [123] and reliable computations will not be presumably possible before one decade. However, since the boundary layer turbulence is induced by the strong wall shear, it might be possible that when the latter is introduced by a forcing exerted directly on the flow (either by a pressure gradient or by a wall motion), the transition to the ultimate regime could be obtained for smaller values of the thermal forcing, affordable to the three dimensional direct numerical simulation by the present computers.…”