Effects of the gravitational force on the convection turbulence driven by heat-releasing point particles.

This article investigates convection turbulence driven by heat-releasing point particles that absorb energy from external sources, incorporating two-way coupling in both momentum and temperature fields while accounting for particle dynamics influenced by Stokes drag and gravity forces. Through direct numerical simulations at two Rayleigh numbers, the study identifies two regimes based on the Froude number: at large Froude numbers, particles are advected throughout the domain reaching a statistically steady state, whereas at small Froude numbers, particles accumulate near the bottom boundary layer, causing simulation breakdown due to high local concentration. The research finds that within the high-Froude regime, transport properties such as mean temperature, heat flux asymmetry, Reynolds number, and viscous boundary layer thickness depend weakly on the Froude number but more strongly on the Stokes and Rayleigh numbers. Scaling laws for the critical Froude number marking the transition between regimes are derived and validated against numerical results, providing insight into particle concentration phenomena in particle-laden turbulent convection driven by heat-releasing particles.