Abstract
Natural convection flow of roof top cross section in a green house has been numerically investigated using a thermal lattice Boltzmann method (TLBM). Two types of thermal boundary condition are considered; uniform and nonuniform bottom heating with symmetrically cold inclined walls. The results are presented as velocity and temperature profiles as well as stream function and temperature contours for different Rayleigh number, Ra, ranging from 10(3) to 10(5) with other controlled parameters. The intensity of circulation is found to be higher and symmetric for lower values of Ra and the asymmetric behavior of the flow about the geometric centre line is seen for higher values of Ra in the case of uniform bottom heating. However, for nonuniform case, multiple circulation cells are observed for different Ra maintaining the symmetrical fluid properties. In addition, the average rate of heat transfer in terms of Nusselt number indicated the lower heat transfer rates for the nonuniform case compared to the uniform heating case. Finally, the results have been compared with the previous published works and found a good agreement.