Contribution to a conference proceedings/Contribution to a book

FZJ-2025-02502

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Unraveling the Boundary Layers of High Rayleigh Number Convection Through Direct Numerical Simulations

Samuel, R. J. (Corresponding author) ; Shevkar, P. P. ; Bode, M.FZJ* ; Scheel, J. D. ; Sreenivasan, K. R. ; Schumacher, J.

2025
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

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Please use a persistent id in citations: doi:10.34734/FZJ-2025-02502

Abstract: We study the behavior of boundary layers in thermal convection at Rayleigh numbers ranging from 10^5 to 10^12 in a box of aspect ratio Γ = 4, and periodically extended sides. We use the GPU accelerated spectral element solver, NekRS, for our simulations. At the highest Rayleigh number, the simulations utilize nearly 3400 A100 GPUs of the JUWELS Booster facility, to cover as many as 40 free-fall time units, enabling us to obtain reliable statistics in steady-state. This demonstrates the excellent scalability of the solver. Moreover, since the focus of the study is on the boundary layers at the top and bottom walls, we ensure that the near-wall regions are well-resolved. We observe that the boundary layers have both shear dominated and plume dominated regions, with a nearly constant area-fraction between these regions. We also study the structure of wall shear-stress fields and their connection to plume structures emanating from the walls.

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Contributing Institute(s):

1. Jülich Supercomputing Center (JSC)

Research Program(s):

1. 5111 - Domain-Specific Simulation & Data Life Cycle Labs (SDLs) and Research Groups (POF4-511) (POF4-511)
2. MesoComp - Order at the Mesoscale: Connecting supercomputing of compressible convection to classical and quantum machine learning (101052786) (101052786)

Appears in the scientific report 2025

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