Научные ведомости БелГУ № 13(68) 2009 146 52. Shur M.L, Strelets M. K., Travin A.K., Spalart P.R. Turbulence modeling in rotating and curved channels: Assessing the Spalart-Shur correction // AIAA Journal. – 2000. – 38;5. – P.784–792. 53. Spalart P.R., Allmaras S.R. A one-equation turbulence model for aerodynamic flow // AIAA Paper. – 1992.– 12;1. – P.439–478. 54. Spalart P.R., Shur M. On the sensitization of turbulence models to rotation and curvature // Aerospace science and technology Journal. – 1997. – 1;5. – P.297–366. 55. Van Leer B., Lee W.-T., Roe P. Characteristic timestepping or local preconditioning of the Euler equations // AIAA Paper. – 1991. – 19;6. – P.1552-1587. MATHEMATICAL MODELLING OF SEPARATED FLOWS ON THE BASIS OF UNSTEADY NAVIER-STOKES EQUATIONS D.A. Redchits Institute of Transport Systems and Technologies NANU, Dnepropetrovsk, Ukraine The Reynolds averaged Navier-Stokes equation is applied to the numerical simulation of unsteady turbulent separated incompressible flows. The one-parameter differential models of turbulence models are used. The solution of the initial equation system is obtained using the implicit finite-volume numerical algorithm which is based on the artificial compressibility method. Besides, overlapped structured grids are applied in multidomain areas. Verification of developed CFD code is fulfilled on problems concerning the circulating flow in the square cavity, the flow near fixed and rotated cylinders. Comparison of of calculations concerning the flow near fixed and oscillating airfoil is carried out. The results of calculations of Darrieus and Savonius rotors with different number of blades and blades with differnt geometrical characteristics are proposed. The analysis of flow near rotors is done. Main stages of vortex development are allocated. The Reynolds number influence on power characteristics of Darrieus and Savonius rotors is found as well as tip-speed-ratio and solidity. Key words: separated flow, Reynolds number, Navier-Stokes equations, imcompressible liquid, vortex, turbulence, Darrieur and Savonius rotors.