Large-eddy simulation of natural convection boundary layer on a vertical cylinder

Large-eddy simulation of natural convection boundary layer along a constant temperature vertical cylinder is studied and the results are compared with experimental data. The highest local Grashof number is Gr(z) = 5 X 10(11). Although there are some discrepancies between the results in the region close to the wall, there is qualitative agreement between them. Mean values of the temperature near the wall show that the conventional law of the wall is valid in this case. However, the region where (v(+)) = r(+), is much smaller than that of forced convection. With respect to turbulence production, the near-wall behavior of turbulent shear stress and normal stresses are investigated and compared with the experimental results. The existence of a negative shear stress region close to the wall in the simulations is confirmed and its influence on stream-wise normal stress is shown. The integral form of the momentum equation suggests that the buoyancy balances the combination of the turbulent stresses and the viscous term. The existence of a region where the energy spectra are proportional to kappa(-3) is verified. (C) 2006 Elsevier Inc. All rights reserved.