An experimental study of the effect of large-scale disturbances on the laminar-turbulent transition in a free-convective layer on a vertical surface

Abstract

The results of an experimental study of a free convective boundary layer on a vertical heated surface are presented in this paper. Particular attention was paid to studying the laminar-turbulent transition zone and determining the boundaries of this zone. The main goal of the present work was to study the possibility of controlling the transition processes by acting on it with various large-scale obstacles located in the region of the laminar section of the boundary layer. A studied free-convection boundary layer is formed on a vertical aluminum plate 90 cm wide and 4.95 m high. Based on the obtained results, it can be confidently stated that with the help of large-scale obstacles, it is possible to significantly reduce the length of the transition zone and thereby bring the beginning of the region with developed turbulent heat transfer closer to the front edge of the surface. Thus, obstacles can be considered as passive elements for controlling the intensity of heat transfer.

Keywords

• natural convection
• laminar-turbulent transition
• heat transfer
• natural convective boundary layer
• experimental study