Investigation of Active Control of Aircraft Wing Tip Vortices and Wake Turbulence

Abstract

The present work was focused on study and application of active flow control methods to alleviate the wake turbulence problem in commercial aircraft. Sinusoidal perturbations were introduced into the tip vortex generated off one of the wings in a two wing system. Various forcing frequencies and oscillation amplitudes were investigated in a towing tank facility. Measurement techniques included invasive and non-invasive methodologies such as flow visualization, hot film anemometry and particle image velocimetry (PIV). Tilting of the plane of the vortices under forcing conditions was observed. The initiation of long-wave Crow instability was observed. This was also confirmed by flow visualization results. For 20Hz forcing frequency, elliptical deformation of the core for both the vortices was observed. This was an indication of short wave Elliptic instability. When perturbed at a particular frequency and amplitude, the overall system showed earlier onset of instabilities.