Effects of Leader’s Position and Shape on Aerodynamic Performances of V Flight Formation

Abstract

The influences of the leader in a group of V – flight formation are dealt with. The investigation is focused on the effect of its position and shape on aerodynamics performances of a given V – flight formation. Vortices
generated the wing tip of the leader moves downstream forming a pair of opposite rotating line vortices. These vortices are generally undesirable because they create a downwash that increases the induced drag on leader’s wing. However, this downwash is also accompanied by an upwash that can beneficial to the follower’s wing flying behind the leader’s one, namely a favorable lift for the follower’s wing. How much contributions of the leader’s wing to the follower’s wing in the V – formation flight is determined by the strength of tip vortices generated by the leader’s wing which is influenced by its position and shape including incidence angle, dihedral angle, aspect ratio and taper ratio.

The prediction of aerodynamic performances of the V–flight formation including lift, drag and moment coefficients is numerically performed by solving Navier – Stokes equations with k - ε turbulence model. The computational domain is defined with multiblock topology to capture the complex geometry arrangement of the V – flight formation.