STRUCTURE OF TURBULENT TEMPERATURE AND VELOCITY FLUCTUATIONS IN THE THERMAL ENTRANCE REGION OF A PIPE
An experimental investigation has been made on the fine structure of turbulent temperature fluctuations and their correlations with velocity in the thermal entrance region of a circular pipe. In the inner layer, overall characteristics of temperature fluctuations and correlations between velocity and temperature fluctuations are almost identical throughout the entrance region. The intermittency of temperature fluctuations takes place near the outer edge of the thermal boundary layer. The distributions of temperature fluctuation intensities are not similar in the entry region. There exist, however, similarities in the profiles of such quantities as velocity-temperature cross-correlation coefficient, turbulent axial heat flux normalized by local mean velocity and mean temperature difference, and the product of intensities of temperature and velocity fluctuations relative to local mean temperature difference and mean velocity. The spectra of temperature fluctuations were also investigated.