Abstract
The partial differential equations expressing the conservation of momentum, mass, and energy for the laminar free convection from a horizontal flat plate, having a finite thickness and length, were transformed into the ordinary differential equations, which were obtained for both the upper and lcwer surfaces of a horizontal plate. Also, it was demonstrated that the ordinary equations for the upper surface were equal to those obtained for the vertical plate, having uniform heat flux studied by E.M. Sparrow, but the equations on the lower surface had the different forms. The distributions of local heat-transfer coefficient and surface-temperature variations on both the surfaces, by considering a plate whose cross section is of a very thin ellipse, were calculated by means of Runge-Kutta's and von Karman-Pohlhausen's methods. It has been shown that the mean heat-transfer coefficient on the lower surface is affected by the thickness of the plate, and it is about 60% of that the vertical plate with same length, and that if mean Nusselt number for the plate with uniform surface heat flux is calculated by using the mean temperature difference over the surface, the results are very close to that for a uniform surface temperature plate.
