Generation of Traveling Waves in a 2D Plate for Future Drag Reduction Manipulation

In most systems, friction drag is an obstacle to be hurdled and is a large source of energy inefficiency in airplanes, ships, pipes, etc. By reducing the amount of friction drag between a fluid and a surface, large energy savings are possible. This study investigates the generation of traveling surface waves propagating in the spanwise direction (perpendicular to flow) that can later be applied to decrease the friction drag in turbulent flow. A thin plate with C-F-C-F boundary conditions is excited by two piezoelectric actuators at the same frequency but with a phase difference between them. The operational deflection shapes are captured at five different frequencies where one to four regions of traveling waves exist in the plate at each frequency, with some moving in opposing directions. The traveling waves have standing waves superimposed, where the form of the standing waves are determined by the participation of nearby modes. This work provides initial assessment on the generation of traveling waves in 2D structures that can potentially be used for drag reduction in the future.