The results of an experimental and numerical research of two-dimensional unsteady flow and heat transfer in the step Formed rectangular cavity of cylinder shaped short channel are presented. Both experimental measurements and numerical simulations are carried out to establish the ability of a time accurate finite element solver to capture the transient flow and heat transfer. Measurements have been performed in incompressible turbulent pipe flow over a range of Reynolds numbers between 5.5 (.) 10(3) and 5.5 (.) 10(4) and temperature 900-3500 K. The results indicate that the presence of the cavity affects the now so, that the streamlines are defected into the cavity and a system of eddies, called cavity vortices, is generated within. Distribution of velocities, temperatures and heat exchange coefficients in the circular zone are studied.