Inviscid wing-tip vortex behavior behind wings in close formation flight

The wing trailing vortex system for wings in close formation flight using a discrete vortex method was investigated. The wing bound vortex system was approximated by lifting lines with elliptic load distributions. The prediction of the wake behavior showed that the distance between the wings has the effect of moving the wake vortices up behind wing tips facing each other. The relative heights between aircraft caused a large asymmetric evolution of wake vortices, which resulted in a change of aerodynamic characteristics. It was concluded that the prediction of the wake roll-up behavior behind aircraft in formation flight might be of considerable importance in the prediction of the aerodynamic performance.