In recent years, the increase in heat generation due to the high performance of equipment has become a major issue. To solve this issue, more efficient heat exchange technology is essential. In this study, we focused on density difference convection in a horizontal cylindrical container, which is one of the phenomena induced inside heat exchangers that use fluids. The driving force, buoyancy, comes from the change in density caused by temperature change. In this study, we performed infrared thermography and PIV to clarify the density difference convection in a horizontal cylindrical container with a free boundary, and then clarified the thermal and momentum transport mechanisms through post-processing such as signal processing and spectral analysis of both the velocity field and the temperature field data.
Nishikawa et al. (2025) studied this question.