The effects of active separation control by steady blowing jets were investigated numerically on three different examples: subsonic flow past Aerospatiale A airfoil at 13º angle-of-attack, transonic flow past NACA 0012 airfoil at 4º angle-ofattack, and transonic flow in linear compressor/turbine cascade. Performed analyses are two-dimensional, flow is turbulent (or transitional) while fluid is viscous and compressible. Jets are positioned along the suction sides of the foils, the first one being located just upstream of the separation point, and modeled by source terms added to flow equations. Several different jet diameters and intensities are investigated. As the choice of turbulence model affects the final solution of Reynolds equations, turbulence is modeled by four different models: Spalart- Allmaras, realizable k-ε, k-ω SST, and γ-Reθ, and a comparison of obtained results is performed. Goals of the study include definition of an adequate numerical setting that enables sufficiently correct simulation of the problems in question as well as evaluation of the possible increase in aerodynamic performances. Lift coefficients, lift-to-drag ratios or relative pressure differences are improved for all controlled cases.