HEATLINE VISUALIZATION OF FORCED-CONVECTION LAMINAR BOUNDARY-LAYERS

This paper reports in closed form the similarity heatfunctions H for l aminar boundary layer flow on a flat wall. Plots of the constant-H lin es ('heatlines') show that the path of convection from a hot free stre am to a cold wall is unlike the path of convection from a hot wall to a cold fluid. The true path of convection in laminar boundary layer fl ow is visualized in charts drawn for both heat transfer modes (cold wa ll, hot wall), several Prandtl numbers (0.02, 0.72, 7) and isothermal walls and constant-flux walls. The paper stresses the heat transfer fe atures that are brought into view for the first time by the heatline p atterns. As a supplementary contribution, the paper reports the exact similarity solution for the wall with uniform flux in the Pr --> 0 lim it, and proposes a closed-form local Nusselt number correlation that c overs the entire Pr range.