Coupled piezoelectric nonlinear transduction array for turbulence manipulation

This article reports on the experimental design and optimization of a piezoelectric bimorph transducer array used to create large amplitude and high frequency vibrations at an airfoil surface demonstrating an active flow control strategy. Broad-band resonant surface vibrations are created with the help of a metal / ceramic composite actuator design which operates in a nonlinear regime. The array design comprises of a flat metallic surface plate which can align perfectly to an airfoil hence resembling a movable wall in a turbulent boundary layer. A phase shifted operation of the actuators results in local displacements that generate transverse surface waves in the turbulent boundary layer. Furthermore, the flow control functionality is validated by performing Particle Image Velocimetry (PIV) measurements in an atmospheric wind tunnel.