Natural convection in a vertical plane channel: DNS results for high Grashof numbers

The turbulent natural convection of a gas (Pr = 0.71) between two vertical infinite walls at different but constant temperatures is investigated by means of direct numerical simulation for a wide range of Grashof numbers (6.0 x 10(6) > Gr > 1.0 x 10(3)). The maximum Grashof number is almost one order of magnitude higher than those of computations reported in the literature so far. Results for the turbulent transport equations are presented and compared to previous studies with special attention to the study of Verteegh and Nieuwstadt (Int J Heat Fluid Flow 19:135-149, 1998). All turbulence statistics are available on the TUHH homepage (http://www.tu-harburg.de/tt/dnsdatabase/dbindex.en.html).). Accuracy considerations are based on the time averaged balance equations for kinetic and thermal energy. With the second law of thermodynamics Nusselt numbers can be determined by evaluating time averaged wall temperature gradients as well as by a volumetric time averaged integration. Comparing the results of both approaches leads to a direct measure of the physical consistency.