Active gurney flaps: Their application in a rotor blade centrifugal field

Miniature trailing-edge effectors are segmented gurney flaps that can deploy to achieve multipurpose functions, such as performance enhancement, noise/vibration control, and/or load control on rotor blades. The unsteady aerodynamics of miniature trailing-edge effectors and a deployable plain flap (with an equivalent lift gain) are quantified experimentally at a reduced frequency of 0.21 and a Reynolds number of 1 × 10⁶. These experiments are also simulated using computational fluid dynamics. The combination of the wind tunnel experiments and computational fluid dynamics are used to quantify the aerodynamic effects of miniature trailing-edge effector deployment to compare their unsteady aerodynamics to plain flaps, and to evaluate the fluid dynamics of miniature trailing-edge effectors against experimental data. The current experiments display unsteady aerodynamics that corroborate previous computational fluid dynamics findings that indicate that miniature trailing-edge effectors shed on-surface vortices during deployment, affecting the unsteady aerodynamics of the system. Computational fluid dynamics also predicted that miniature trailing-edge effectors require 1/55 power to deploy compared to a plain-flap configuration. Power reduction is a key attractor for the integration of devices on smart rotors. This work is concluded with an effort that displays that the low power requirement of miniature trailing-edge effectors enable simple deployment methods, such as the use of pressure differentials inherent to the rotor blades. The proposed pneumatic miniature trailing-edge effector configuration was tested at centrifugal forces representative of helicopter rotor blades.