Quantum mechanics

Compressibility

Turbulence

Nusselt number

Heat transfer

Reynolds number

Rayleigh number

Large eddy simulation

Natural convection

Temperature gradient

Thermodynamics

Physics

Optics

Compressible flow

Boussinesq approximation (buoyancy)

Rayleigh scattering

Work (physics)

Meteorology

Asymmetry

Mechanics

Pressure gradient

Convection

Proceeding of THMT-12. Proceedings of the Seventh International Symposium On Turbulence, Heat and Mass Transfer Palermo, Italy, 24-27 September, 2012

A Rayleigh-Benard problem (RB) describes thermally driven flow against gravity between two heated plates. The fluid is accelerated by local density differences and a resulting pressure gradient. Directly at the heated walls the temperature distribution is determinate by increasing temperature gradients. In the centre region convective mass exchange is dominant. Density changes due to temperature differences are considered in the Large Eddy simulation by a compressible coupled model. Previous work investigates similar setups with a Boussinesq-approximation [9, 10]. The investigated Rayleigh-numbers lie between 6 · 107 and 4 · 108. A direct correlation between Rayleigh- and Nusselt-number is observed. The temperature profile shows an asymmetry, which is explainable according to the density weighted velocity profile. [1] also detects an asymmetry in the temperature profile of water for a RB with non-boussinesq effects. Simulation results are compared with analytical model results [4, 5] and experimental data [2].

Modelling turbulent heat transfer of a Rayleigh-Benard problem with compressible Large Eddy simulation