Experimental study of the influence of the shape of the gap between the rib and flat plate on the near-wall flow structure and heat transfer

The article presents an analysis of the results of an experimental study of the dynamic and thermal characteristics of the turbulent boundary layer of the air near a heated plate at $q_w = \mathrm{const}$ with rectangular ribs having slit channels of different geometry: confusor, diffuser, and plane-parallel. The slit channel is located between the plate and the lower rib wall. The results are compared with similar data for a solid rib without the slit channel. A Pitot–Prandtl microprobe with a microthermocouple and the Dantec Dynamics hot-wire anemometer were used, thus making it possible to study the laminar sublayer, the transition domain, and the outer part of the boundary layer. The influence of the slit profile on the average and the pulsation characteristics of the turbulent dynamic and thermal boundary layers in the median section of the plate with the slit rib is revealed. It is found that the separated zone disappears in the flow behind the ribs with the confusor slit.