Abstract: An experimental study of separation control by the vortex generators in a subsonic diffuser has been conducted. The flow regime of the two-dimensional diffuser is at the large transitory stall regime. The high efficiency of using vortex generator to control the flow separation in the diffuser can be obtained, if the geometrical parameters, the configuration and the installed location of the vortex generator are selected carefully. The static pressure recovery coefficient Cp is inereased as higin as 66% on separated wall of tiie diffuser, and the steady total pressure loss, the statie and dynamic distortion are also reduced enormously. In shert, the proper vortex generator configuration and the geometrical parameters are selected for separated diffuser, it will be effective to suit for wide range Maeh number at the diffuser entrance. The present results show that the high efficicney could be held until .A10 = 0.61.

Key words: subsonic diffuser, flow separation, vortex