A piezo-actuated closed loop MEMS system for active delay of transition

This paper presents the design, fabrication and application of a highly integrated closed loop MEMS system for an active control of aerodynamic flow instabilities across airfoils. A special piezo-polymercomposite (PPC) technology was used for the fabrication of powerful piezo-microactuators that were integrated with hotwire flow sensors and a digital control system. This work shows first wind tunnel experiments that prove the principal suitability of the developed device for dampening disturbances in the boundary layer. The local amplitudes of natural disturbances, so called Tollmien-Schlichting (TS) waves, have been reduced by 42%.