Скачать с ютуб DNS of an air-filled Rayleigh-Bénard convection at Ra=1e8 and 1e10 and Gebhart number Ge=0 and Ge=1 в хорошем качестве

DNS of an air-filled Rayleigh-Bénard convection at Ra=1e8 and 1e10 and Gebhart number Ge=0 and Ge=1

Four direct numerical simulations (DNS) of an air-filled (Pr=0.7) Rayleigh-Bénard configuration at Ra=1e8 (left) and 1e10 (right) and Gebhart number Ge=0 (top) and Ge=1 (bottom), respectively. The non-dimensional Gebhart number (also known as the dissipation number) appears when considering the viscous dissipation effects in the internal energy equation. Although they are usually neglected (i.e., Ge=0), these effects are relevant in geophysical flows or in devices operating at high rotational speeds. Simulations were carried out on the MareNostrum4 supercomputer using: (i) for Ra=1e8: 128CPUs and a 17M mesh (400x206x206), and (ii) for Ra=1e10: 1024CPUs and a 600M mesh (1024x766x766). The grid is stretched out away from solid walls through a tanh-function. Numerically, the governing equations were discretized in space on a Cartesian staggered grid using a finite-volume symmetry-preserving scheme. Moreover, a novel energy-consistent discretization of the viscous dissipation function has been used: it guarantees that the energy exchange between kinetic and internal energy is exactly preserved. For details, see: B.Sanderse and F.X.Trias. "Energy-consistent discretization of viscous dissipation with application to natural convection flow" https://arxiv.org/abs/2307.10874 It displays the time evolution of the instantaneous temperature field once an statistically steady state is reached. The effect of Ge-number is clearly for observed both Ra-numbers: viscous dissipation effect increases the average temperature. Data at Ge=0 is publicly available at: https://www.cttc.upc.edu/downloads/RBC/