Flap Sizing for Wake Vortex Instability

The authors explore the possibility of designing the flap system on a given wing for enhanced Crow instability. The problem motivation in terms of increased traffic volume and increased safety is described. A brief review of the technical literature is given. An exploratory two-dimensional potential flow formulation is presented. A generic wing and flap combination is used for trade-off studies. The authors show that the frequency with which the flap-tip and the wing-tip vortex filaments swirl around each other can be tuned to match that which corresponds to the largest rate of amplitude growth in the wake. The extent of the analysis being two-dimensional, the authors suggest careful wind- or water-tunnel testing in three dimensions to validate the concept.