Natural convection in triangular enclosures is an important problem. It displays well the generic attributes of this class of convection, with its dependence on enclosure geometry, orientation and thermal boundary conditions. It is particularly rich in its variety of flow regimes and thermal fields as well as having significant practical application. In this paper, a comprehensive view of the research area is sought by critically examining the experimental and numerical approaches adopted in studies of this problem in the literature. Different thermal boundary conditions for the evolution of the flow regimes and thermal fields are considered. Effects of changes in pitch angle and the Rayleigh number on the flow and thermal fields are examined in detail. Although most of the past studies are in the laminar regime, the review extends up to the recent studies of the low turbulent regime. Finally, areas of further research are highlighted.

In this study, we present a copper nanowires (CuNWs) based spray deposition process for the fabrication of transparent heaters and thermo-acoustic loudspeakers. We developed a scalable and solution-based synthesis process for CuNWs, which allows to fabricate spray deposited transparent electrodes (TEs) that show performances comparable to indium tin oxide (ITO) based TEs, at much lower material and deposition costs. Without any post-processing, the CuNWs films exhibit a sheet resistance as low as 12.6 1/2 at a high transparency of 77 %. CuNW-based transparent heaters and thermo-acoustic loudspeakers are accurately characterized and modelled in both the thermal and the acoustic domain, showing performances aligned with the state-of-the art.