Display Abstract

Title Rayleigh-B\'{e}nard convection at finite Prandtl number: bounds on the Nusselt number

Name Camilla Nobili
Country Germany
Email camilla.nobili@mis.mpg.de
Co-Author(s) Felix Otto and Antoine Choffrut
Submit Time 2014-02-27 09:52:08
Session
Special Session 43: Harmonic analysis tools for fluid mechanics
Contents
We consider Rayleigh-B\'{e}nard convection at finite Prandtl number as modelled by the Boussinesq equation. We are interested in the scaling of the average upward heat transport, the Nusselt number $Nu$, in terms of the Rayleigh number $Ra$, and the Prandtl number $Pr$. Physically motivated heuristics suggest the scaling $Nu\sim Ra^{\frac{1}{3}}$ and $Nu\sim Ra^{\frac{1}{2}}$ depending on $Pr$, in different regimes. In this talk I present a rigorous upper bound for $Nu$ reproducing both physical scalings in some parameter regimes up to logarithms. This is obtained by a (logarithmically failing) maximal regularity estimate in $L^{\infty}$ and in $L^{1}$ for the nonstationary Stokes equation with forcing term given by the buoyancy term and the nonlinear term, respectively. This is a joint work with Felix Otto and Antoine Choffrut.