"Hot channels" (HC), formed by a rapid energy release in a gas, exhibit turbulent mixing and cooling, and their life time can be several orders of magnitude shorter than the molecular heat conduction time scale. Picone and Boris (1983) suggested that turbulent mixing results from the vorticity generation by the baroclinic mechanism during the early, shock-wave dominated stage of the dynamics. More recently, alternative scenarios of vorticity generation in the HCs were suggested. This work investigates the vorticity generation and turbulent cooling of the HCs by hydrodynamical simulations in two dimensions. Assuming small perturbations of the cylindrical shape of the energy release region, we follow the evolution of several HCs and determine their cooling time. We identify the details of vorticity generation which results in turbulent flow and fast mixing of the cold ambient gas into the HC. The simulations support, with some modifications, the Picone-Boris scenario. The simulated cooling time scale is in good agreement with experimental results, and the cooling process can be described as turbulent diffusion. The width of the mixed region shows dynamic scaling and compares well to experimental data.