Abstract
Active control of flow separation has been investigated to reduce energy losses in fluid machinery. In order to improve the lift drag ratio in unsteady flow, feedback flow separation control was investigated by using a dielectric barrier discharge plasma actuator (DBD-PA) and a fiber Bragg grating flow sensor (FBG-FS) under periodic flow separation by oscillating the wind tunnel test section wall. Tangential jets were generated from sheet-type DBD-PAs and string-type DBD-PAs. Active control of the tip leakage flow was also demonstrated in 2D and 3D models of the turbine blade tips by using string-type and ring-type DBD-PAs embedded in the casing wall. DBD plasma was formed selectively in the regions where the turbine blade tips come very close to the casing wall. This reduces the turbulent intensity caused by the tip leakage flow by simply applying high voltages at radio frequencies to the DBD-PA.
