Velocity and Temperature Measurements in a Natural Convection Boundary Layer Along a Vertical Flat Plate

T. Tsuji Y. Nagano Department of Mechanical Engineering Nagoya Institute of Technology, Nagoya, Japan l lA turbulent natural convection boundary layer along a vertical flat plate in air is investigated with hot-wire techniques. Profile measurements of mean velocity, mean temperature, and turbulent quantities, which are obtained well into the wall region, clarify some characteristics peculiar to the turbulent natural convection boundary layer and different in various respects from those in forced convection. The results presented include important knowledge concerning the concept of the viscous sublayer, the availability of the conventional analogy between heat and momentum transfer, Reynolds stress, and turbulent heat fluxes. The reliability of the measurements is verified through theoretical considerations. Also, the scaling of the turbulent natural convection boundary layer is discussed from the experimental standpoint in terms of mean velocity, mean temperature, and velocity and temperature fluctuation intensities. The information obtained in the present study will be very useful for the theoretical study of turbulent natural convection using turbulence models.