Effects of geometry and orientation on laminar natural convection from isothermal bodies

The effects of body shape and orientation on laminar natural convection heat transfer from isothermal, two-dimensional, and axisymmetric bodies are investigated. A new form of the body-gravity function is presented and its behavior is examined for various body shapes and orientations. The square root of the total surface area is obtained from the analysis as the charateristic body length. A definition of the aspect ratio is introduced, which can be used consistently for both two-dimensional and axisymmetric bodies. The resulting body-gravity function is observed to be weakly dependent on geometry and orientation of the bodies for a range of the aspect ratio from approximately 0.2 to 5, over which the body-gravity function resulted in a good agreement with values obtained from the existing experimental data.