Vortex topology of wing tip blowing

An experimental investigation was conducted to study the effect of continuous blowing from high aspect ratio jets near the tip on tip vortex in the near wake. This study followed a previous study and focused on the effect of two new parameters: the shape of the tip and the longitudinal position of the blowing slot. Velocity measurements were taken, using a PIV system, around the tip and in the near wake of a rectangular wing, which was equipped with several blowing slots. The effect was compared to that of the previous study. The results showed that the tip shape is an important parameter, influencing the formation and characteristics of the tip vortex and thus leading to different flowfields in the near wake. Depending on the blowing configuration, a round tip can lead to a more diffused trailing vortex or to multiple coherent vortices, stronger than those produced by a square tip. The round tip also promotes the Coanda effect, which influences the structure of the vortex. The longitudinal position of the blowing slot is also an important parameter. It does not change the general topology of the near wake but when the blowing slot is located further downstream it retains more of its velocity leading to higher crossflow velocities in the near wake.