The three-dimensional turbulent convectional flows of viscous and incompressible fluid in a rectangular parallelepiped numerically is simulated at heating from below. The horizontal boundaries are stress-free and isothermal. The calculated time spectrum of temperature pulsations at supercriticality is equal to 410 in centre of convective cell has a good agreement with experimental data for convection in cryogenic He. The Obukhov – Bolgiano spectra k−11/5, k−3 and k−5 have been found for velocity pulsations.
