Structural Characteristics of Turbulent Natural-Convection Boundary Layer along a Vertical Flat Plate Heated Plate at High Temperature

摘要

The structural characteristics of a turbulent natural-convection boundary layer in air along a vertical plate heated at high temperatures have been experimentally investigated, especially paying attention to large-scale fluid motions in the outer region, which is closely connected with the turbulence generation. The two-dimensional velocity vectors in the boundary layer were measured with a particle image velocimetry at the wall temperature T{sub}w = 300°C. As a result, it was revealed that the effects of a strong heating on the structure of the velocity field in the outer region were quite small, e.g., the profiles of higher-order statistics such as skewness and flatness factors of fluctuating velocities were similar to those observed at low wall temperatures. In addition, the scales of fluid motions remained despite a remarkable increase in the wall temperature.