Visualisation of natural convection in an isosceles triangular enclosure heated from below

The natural convection flow in an isosceles triangular enclosure subject to heating from below and simultaneous cooling from above is visualized using a shadowgraph technique. It is observed from the present experiments that the transient flow development in the enclosure due to abrupt heating and cooling through the boundaries can be classified into three distinct stages, a startup flow stage, a transitional flow stage, and a quasi-steady flow stage. The major flow features at each of the three stages are described, and the dependence of the flow development on the Grashof number is also discussed. The present flow visualization demonstrates that the natural convection flow remains approximately symmetric at all stages and for all the tested Grashof numbers