Experimental investigations of the effect of wing elastic deformations on aerodynamics

The effect of elastic deformations on the aerodynamic performance of a delta wing with 40 deg sweep angle was studied in wind tunnel. The laser vibration measuring apparatus was used to measure the vibration mode and deformation of the wings. The experimental results indicated that, comparing with the rigid wing, the elastic wing can greatly improve the wing aerodynamic performance in low Reynolds number, increasing the lift coefficient and the lift-drag-ratio at small angles of attack, this is of great advantage to flight. Meanwhile, the angle of attack at which the mean deformation of the elastic wing apex achieves maximum is α = 15°, this value is nearly the same as the angle at which the vortex breaks down at the wing tip for the rigid wing; and the rms of both wing tips and apex reaches maximum value for elastic wing around the stall angle α = 20°.