Wind loads and control of flexible structures embedded in a turbulent boundary layer: Mechanical control

We investigate experimentally the flow around a flexible rectangular thin plate positioned normal to the wind direction and embedded in a thick turbulent boundary layer. The purpose of the study is to reduce the plate oscillations caused by unsteady wind loads. Two methods were tested. First we used mechanical Piezo-electric actuators attached to the plate while the second method used fluidic actuators around the plate edges. The two methods were applied with similar closed-loop control principles: Strain Gauge (SG) sensors captured the plate's oscillations and a simple phase-lag and gain was used to attenuate the oscillations. In the current paper we focus on the mechanical attenuation mechanism. Two Piezo electric elements were bonded to the plate close to its fixed end. The results show a reduction of 20-30% of the plate oscillation compared to the uncontrolled case. This stage is a reference case for the other part of the study that focuses on fluidic control.