Lift and Drag behavior of a low Reynolds wing section submitted to a nearby stream wise vortex

The purpose of this work is to determine the influence of spiral vortical structures upon low Reynolds number airfoils. Our main goal is to find out how such vortical structures, generated by a delta wing, modify the aerodynamic coefficients and the overall behavior of those airfoils. The tip vortex wake produced by one aircraft could affect other aircrafts in different ways over other airplanes depending on whether it flows under, over or across its wing. In all cases the fluid pattern will influence the local circulation affecting the overall lift. The purpose of this work is to study this influence. The instantaneous flow velocities inside and outside the vortices will be measured by means of a hot wire anemometry (HWA). The tested airfoil is a modified Eppler 387. The experiments were carried out in a low turbulence flow (1.8%) at a Reynolds number of 350.000 (based on the airfoil chord and on the free stream velocity).