Experimental techniques of the study of vortex structures caused by point injection on the leading edge of the oblique wing Tolkachev S.N. Gorev V.N. Zharkova G.M. Kovrizhina V.N.

Boundary layer on the oblique wing

Experimental setup Slip angle: 45° Angle of attack: -0.1° Free-stream flow velocity: 4.2 m/s

Boundary layer velocity profiles on the attachment line

Velocity disturbances for two regimes of blowing Stationary disturbance Z-direction distribution in 5 mm from the hole in Y-direction for two regimes of blowing

Measurement points for 3d

Stationary disturbances 3d Strong blowing

LC thermography method b) a) Mechanism b) Location on the wing c) features: Multiuse Qualitative ohmic heater with uniform distribution of heat power needed Qualitative digital camera needed to receive the right color capture Lag attainment of stationary regime is about 20-30 minutes (wing design heating) Stationary disturbances visualization Heat influence on the flow (destabilize) c) Typical visualisation picture for undisturbed flow

Experimental setup Slip angle: 45° Angle of attack: -2.6° – 0.2° Free-stream flow velocity: 3.4 – 9.4 m/s

Disturbance point injection relative to attachment line position U∞ = 3.4 m/s Vjet = 13 m/s

Influence of blow velocity U∞ = 3.4 m/s

Conclusion Point injection on the leading edge of the oblique wing forms the pair of counter rotating vortices The behaviour of the stationary disturbance depends on the blowing speed The increase of the blowing speed leads to the decrease of the angle between the disturbance trajectory and attachment line The weak blowing can be used for investigation of the boundary layer on the oblique wing leading edge The strong blowing leads to complication of the flow and appearance of the strong nonlinear effects