Abstract
In order to reduce an aerodynamic noise generated from the flat plate cascade, we attempted to flow and noise control by using plasma actuator. In the case of non-resonance condition (such as the Aeolian tone noise generated from a single flat plate), aerodynamic noise levels increase by using PA. This is considered because that PA supply the momentum to the separated flow near the leading edge, flow separations are suppressed and the share flow becomes stronger than that of without PA. As a result, aerodynamic noise is increased by using PA in non-resonance condition. The effect of noise control is proportional to the supplied voltage and driven frequency of PA. On the other hand, in the case of resonance condition of flow and sound fields, sound level can be reduced by using PA. When the acoustic resonance occurs in flat plate cascade, phase of vortex shedding is locked by the generated sound. The experimental results showed that PA was control the phase and intensity of the vortex shedding near the reading edge, and it is less likely to become strong acoustic resonance field is formed. These facts indicate that the control of unsteady aerodynamic flow and sound field characteristics must be discussed when the effectiveness of noise control with PA is evaluated.
