Turbulent natural convection on a vertical plate and in a vertical layer

Abstract

An experimental investigation was carried out on the hydrodynamics of a turbulent freeconvection boundary layer at a vertical plate and in a vertical film of ethyl alcohol closed at both ends. Herein are presented longitudinal component profiles of the mean velocity vector and fluctuation rate of the same velocity vector component. On the basis of the present data and experimental results of other authors, the existence is shown of a quasi-stationary wall layer in the turbulent boundary layer at a vertical plate, the thickness and maximum velocity of which satisfy the condition Re 1Pr 1 2 = U max δ1 (va) 1 1 = const. It is found experimentally that along the middle of the vertical cross-section in the central part of the film the temperature gradient is dT/ dx = const. Within the region of constant temperature gradient in the turbulent boundary layer there is a quasi-stationary wall layer for which Re 1= 1 2 = U max δ1 v = const. The number Re 1, is a function of the relative temperature gradient 1 ΔT dT dx in the external side of the boundary layer.