Wake Vortex Alleviation Using Rapidly Actuated Segmented Gurney Flaps

A study to assess the potential for using rapidly actuated segmented Gurney flaps, also known as miniature trailing-edge effectors, for active wake vortex alleviation is conducted. Experiments are performed using a half-span model wing with NACA 0012 shape and an aspect ratio of 4.1. The wing is at an 8.9-deg angle of attack and the chord-based Reynolds number is around 350,000. It is equipped with an array of miniature trailing-edge effectors that extend 0.015 chord lengths perpendicular to the freestream on the pressure side of the wing when deployed and sit just behind the blunt trailing edge when retracted. Measurements of section lift coefficient and the velocity field in the intermediate wake using dynamic particle image velocimetry and a five-hole probe delineate the time-varying perturbation imparted by the miniature trailing-edge effectors upon the trailing vortex while keeping the lift nearly constant. The data are used to form a complete initial condition for a vortex filament computation of the far-wake evolution. Cases at the model-scale and full-scale configurations are computed. The results show that actuator-induced perturbations can be used to excite a variety of inviscid vortex instabilities. [PUBLICATION ABSTRACT]