Rayleigh number is used as criterion to identify the nature of flow is laminar or turbulent. In general, for Ra < 10
6
, the flow is usually observed to be laminar and for Ra < 10
8
, the flow is considered to be turbulent (ANSYS Inc., 2006). In this study, the Rayleigh number was found to be less than 10
6
and hence in the analysis the flow was assumed to be laminar.