High-resolution simulation boundary layer studies in Rayleigh-Bénard convection

We analyse the near-wall statistics of Rayleigh-Bénard convection through high resolution direct numerical simulations of convection in a box with periodic sides and a modestly large aspect ratio of 4. The Prandtl number is Pr = 0.7, while the Rayleigh number is 10⁵ < Ra < 10¹⁰. We analyze the time-series and temporal statistics of volume averaged and wall Nusselt numbers, as well as mean kinetic energy. Additionally we present the velocity and temperature statistics in the viscous and thermal boundary layers. These new DNS data are also related to our previous high-Rayleigh number DNS in slender cells. We employ the latest GPU-accelerated spectral element solver, NekRS, which is derived from the widely used Nek5000 code, for our simulations. Weak and strong scaling performance of this new solver for simulations of thermal convection is also discussed in brief.