DOI: 10.1615/ICHMT.2009.TurbulHeatMassTransf
ISBN Print: 978-1-56700-262-1
ISSN: 2377-2816
Analysis of the fluctuations of the wall heat transfer rates in turbulent natural convection channel flow
RESUMO
We performed a direct numerical simulation of the turbulent natural convection flow in a vertical plane channel. The Prandtl number and the Rayleigh number, based on the temperature difference and the distance between the two vertical walls of the channel are, 0.7 and 5.4·105, respectively. When the flow was statistically fully developed, we recorded the time evolution of the velocities and temperatures during 0.5 non-dimensional time units, which correspond to about 300 times the characteristic time scale of the fluctuations of the wall heat transfer rates. Using a conditional average technique, we extracted from the database the averaged flow structures responsible for the extreme fluctuations of the wall heat transfer rates on the hot and cold walls.