Active Control of Flow and Aerodynamic Noise over a Cavity Using Thin Ceramic Actuators

An experimental investigation attempting to actively control the flow over a cavity and to reduce the aerodynamic noise is carried out. Thin piezoelectric pieces are used as the actuators. Two types of piezo-ceramic devices, a uni-morph type and a bi-morph type, are compared. Experimental results show that both types are capable of generating a flow field that is 180 degree out of phase along the spanwise direction. However, the uni-morph type piezo-ceramic actuator pieces can control the flow under wider range of experimental conditions. The unimorph type actuator pieces are also more effective in suppressing the aerodynamic noise.