Experimental study of wall-free non-stationary vortices generation due to air unstable stratification

The purpose of the paper is to find the heating rates of underlying surface and air temporal and spatial temperature shear which lead to the stable genesis of wall-free non-stationary vortices. These vortices were generated over underlying surface of aluminum sheet due to its controlled heating from below as a result of development of unstable stratification of air. It is strictly emphasized that in contrary of previous studies no mechanical rotation devices and/or underlying surface rotation were used for the vortices generation.