An eddy noncompressible gas flow is described by nonstationary Navier-Stokes equations. A projection Chorin-Temam method is used for the time integration of the nonstationary Navier-Stokes equations. A computational scheme of a discontinuous Galerkin method is applied for the H(div) finite element discretization. Mathematical modeling results of a gas flow in a channel with a variable diameter are presented. A comparative analysis of the mathematical modeling results with experimental data is given.