2021/04/07 by Philipp Reiter, Olga Shishkina, Reiter, Philipp +5 · 1 citation
Earth and Planetary Sciences · Engineering · Physics and Astronomy · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Turbulent Flows #Meteorological Phenomena and Simulations #Solar and Space Plasma Dynamics
paper · pdf · doi:10.48550/arxiv.2104.03209
openalex publication_date 2021/04/07 · openalex created_date 2022/07/25 · openalex updated_date 2026/07/28
Turbulent thermal convection is characterized by the formation of large-scale\nstructures and strong spatial inhomogeneity. This work addresses the relative\nheat transport contributions of the large-scale plume ejecting versus plume\nimpacting zones in turbulent Rayleigh-B 'enard convection. Based on direct\nnumerical simulations of the two dimensional (2-D) problem, we show the\nexistence of a crossover in the wall heat transport from initially impacting\ndominated to ultimately ejecting dominated at a Rayleigh number of Ra\≈ 3\n\× 1011. This is consistent with the trends observed in 3-D convection\nat lower Ra, and we therefore expect a similar crossover to also occur there.\nWe identify the development of a turbulent mixing zone, connected to thermal\nplume emission, as the primary mechanism for the crossover. The mixing zone\ngradually extends vertically and horizontally, therefore becoming more and more\ndominant for the overall heat transfer.\n