No abstract

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.

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This work outlines results of an experimental investigation of vortex core properties of a finite span wing and a helicopter rotor model operating at hover mode. Experimental data was obtained using Stereo-PIV in T1-K wind tunnel at KNRTU-KAI named after A.N. Tupolev. An empirically derived formula is proposed, allowing to estimate the dependence of the vortex core size from the threshold Q-value. The wing tip vortices were measured for different angles of attack. The tip vortices from the rotor blades were measured at two collective pitch angles. The results indicate that the obtained empirical equation can be used to estimate the impact of the lowest threshold Q-value selection on the size of the vortex core, which facilitates a more objective approach compared to known methods, when used to eliminate non-essential vortical regions.