Abstract
We have investigated experimentally the spatio-temporal characteristics of turbulent thermal boundary layers developing over a heated flat plate with various thermal boundary conditions. A ladder-structured temperature probe consisting of 10 cold-wires 3 μm in diameter has been used to measure temperature fluctuations simultaneously at the representative points - from the immediate vicinity of the wall to the outer region - in the thermal boundary layer. The present measurement technique enables us to investigate the effects of the wall thermal boundary condition on the spatio-temporal behaviors of the turbulence quantities of the thermal field. From the conditional sampling and averaging based on the VITA method with the temperature slope criterion, it is found that the spatio-temporal characteristics of temperature fields are strongly affected by the thermal boundary conditions.
