Publication Date:
2023-08-02
Description:
Body forces such as gravity can drive convective motion in fluids. Convection due to thermal gradients and the resulting buoyancy force is called thermal convection and occurs ubiquitously in nature, e.g. as one of the driving mechanisms of convection in the interior of stars and planets such as the Earth’s outer core and mantle, as well as in the Earth’s oceans and its atmosphere. We present results on DNS of thermal convection in an internally heated, non-rotating full sphere with different boundary conditions. The non-dimensional control parameters of this problem are the Rayleigh and Prandtl numbers, representing the strength of the thermal forcing and the ratio of the viscous and thermal diffusivities respectively. We aim to characterise fluid flow and heat transfer in a wide range of parameters, using a global Reynolds number as a measure for the vigour of the flow and the Nusselt number quantifying the strength of heat advection as primary diagnostics. DNS are run up to a Rayleigh number appr. 10^8 times the critical Rayleigh at a Prandtl number of unity, yielding scaling relations between the diagnostics and Ra up to this regime of strong turbulence. The simulations were performed using the fully spectral, efficiently parallelised MHD/fluid dynamics code QuICC.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
