Piezo-Actuators for Gurney flap concept

This document describes the Naca blade considered, details the requirements for the blade and contains data on the dynamic behaviour of the blade and its aerodynamic performance. In this report details the various technologies available for piezoelectric actuators which ranges from stack and patch actuators to linear ultrasonic actuators. It details the methods to solve analytically the piezoelectric equations for standard piezoelectric actuators to have their characteristics. Finally, it presents in an applications part the commercial solutions available and their performances relative to each others. [3]: A. Paternoster, Assessment of mechanical constrains on a Gurney flap with CFD computation for IGOR project, Here are presented the CFD computations realised to investigate the mechanical energy required for the gurney flap actuations. The computations are made in steady-state. The objective was to determine a higher bound for the mechanical work the actuator needed to perform. This article reviews the Gurney flap among other lift improvement mechanisms. It explains the aerodynamic phenomenon behind the lift improvement achieved by Gurney flaps. It displays also lift and drag measurements for various angles and positions of the Gurney flaps over a wide range of angles of attack. The authors conclude the Gurney flap improves the lift coefficient for subsonic and transonic speeds and that its effect is maximised when placed at the trailing edge. This article focuses more on the application of Gurney flaps for rotorcrafts. It presents a CFD computation of the Gurney flap on a Naca 0012 airfoil. Yee concludes that the Gurney flap should not be longer than 2% of the chord length to avoid an increase in drag. He states that the Gurney flap improves the airfoil behaviour in light stall conditions but could not conclude for high angles of attack and deep stall conditions. The bases for active noise reduction are stated in this detailed review of the blade dynamic behaviour and its interaction with vortexes. Active control of vibrations requires excitation at frequencies equal to 4/rev. acoustic benefit for the helicopter today and tomorrow, 34 th European Rotorcraft Forum Liverpool,