2025/11/03 by F. Kupka, D. Fabbian, Kupka, F. +7
Engineering · Physics and Astronomy · Computer Science · #Fluid Dynamics and Turbulent Flows #Solar and Space Plasma Dynamics #Nonlinear Dynamics and Pattern Formation
paper · doi:10.48550/arxiv.2511.01582
Horizontally-periodic Boussinesq Rayleigh-Bénard Convection (RBC) is a simple model system to study the formation of large-scale structures in turbulent convective flows. We performed a suite of 2D numerical simulations of RBC between no-slip boundaries at different Prandtl (Pr) and Rayleigh (Ra) numbers, such that their product is representative of the Sun's upper convection zone. When the fluid viscosity is sufficiently low (Pr \lesssim 0.1) and turbulence is strong (Ra > 106) we find that large structures begin to couple in time and space. For Pr = 0.01 we observe long-lived swaying oscillations of the upflows and downflows, which synchronize over multiple convection cells. This new regime of oscillatory convection may offer an interpretation for the wave-like properties of the dominant scale of convection on the Sun (supergranulation).