Boundary Layer Oscillations over a Resonant Surface

Abstract

The boundary layer is observed in low-speed flow over a dispersively-coupled system of acoustic resonators. It is found that oscillations in the laminar layer are strongly excited by this model of a passive, flexible wall. The ``geometry'' of this process differs from that expected with a real membrane, however, due to the details of the wall construction. A different set of laminar oscillations dominates the flow over the middle of the surface, producing turbulence in a manner controlled by the spanwise variations in the wall. The importance of the nature of this transition process to other shearing flows is discussed.