Stellar envelope is treated in terms of hydrodynamics, as a turbulent, non-stationary, moving medium. The formulation of the problem has been carried out without regard to the way in which the envelope has been formed: the material is ionized hydrogen inside the gravitational field of the star. Heat conduction and the radiation pressure are not considered. The angular momentum is being transferred through turbulence friction while the transfer of energy proceeds through radiation. Collective mean values of the physical quantities are introduced and acoustic model of turbulence with non-linear pulsations presented. The complete system of equations of turbulent motion adjusted to the mean values, is developed.