HEAT-TRANSFER AND FLUID-FLOW OF NATURAL-CONVECTION ALONG A VERTICAL FLAT-PLATE IN THE TRANSITION REGION - EXPERIMENTAL-ANALYSIS OF THE WALL TEMPERATURE-FIELD

Heat transfer and fluid flow of natural convection along a vertical Rat plate were experimentally investigated in the transition region. Local hear transfer coefficients along a vertical flat plate were measured to distinguish the first transition region. The wail temperature and fluid flow were then visualized using a liquid crystal sheet and water-soluble fluorescent paint. Also discussed are the characteristic statistical quantities with the aid of visualizations for the velocity and temperature fields. II was revealed from a series of experiments that horseshoe-shaped low-temperature patterns appear on the wall and that they play a significant role in heat transfer. When the data was ensemble-averaged it was found that the characteristic time-and-space scales of the patterns are statistically independent of not only heal flux but also the position in which they occur. Moreover, W-shaped flow patterns, which possess three-dimensional and unstable structures, appear in the near-wall region. They play a significant role in the laminar to turbulent transition.