Visualization of thermally induced air flows in an enclosure heated from below with large characteristic length and small driving temperature differences

The paper deals with technique for visualizing thermally induced flow at high Grashof numbers. The flow is generated inside a relatively tall chamber by means of an electrically heated rectangular slab. Visualization is accomplished by adding metaldehyde particles to the air flow and photographing the luminous diffusion against a dark background. Flow patterns obtained by the technique are given and discussed.