Heat transfer on a flat plate in conditions of hydrodynamically stabilized turbulent boundary layer flow

Experimental data [i] on heat transfer on a heat plate with longitudinal flow of air show evidence of the existence of an unstable regime in the region RexI < I00,000, in which the distribution of local heattransfer coefficients along the surface has quite a complex, and at first sight a random, nature. Since the experiment in [I] was performed on a relatively short plate, the variation in the heat-transfer law for Rex1 < i00,000 could be a consequence of two quite different phenonema. There is no doubt that the nature of the heat transfer in the entrance section is dictated to some extent by the shape of the entrance, even if the boundary layer is assumed to be turbulent everywhere. However, under conditions of developed turbulent motion of an air stream, near the leading edge of the plate a laminar boundary layer can exist, which is unstable at the stagnation point, and later undergoes transition to a turbulent boundary layer [2]. Unfortunately, the results given in [i] do not afford a sufficiently clear answer to the question as to which of the above factors plays the dominant part in generating the transition.