Results of an experimental investigation related to near-field wing tip vortices are presented. The measurements were carried out using a PIV-system in T-1K wind tunnel of KNRTU-KAI. Q-criterion and crosssectional lines method were used to determine vortex core locations, which showed a good agreement. It is shown that the circulation of tip vortices remains constant at low to moderate angles of attack, and decreases in the stream-wise direction for higher angles of attack. It is also shown that the vortex core radius increases in the stream-wise direction, taking larger
values at higher angles of attack.