New method of improving the aircraft aerodynamic performance in the process of aircraft landing

In order to improving the aircraft aerodynamic performance in the process of aircraft landing,a new method is presented: to design a part of the upper surface of the airfoil profile to change into a movable part.When the airplane accesses to the relatively larger angle of attack during the period of landing,a step can be formed on the upper surface by the movable part,thus a stable trapped vortex is generated.By joint operation of a Gurney flap,both effects of improving the lift and the stall angle of attack will be achieved,while drag of airfoil profile will also be increased.By carrying the above method into NACA2415 airfoil,the numerical results show that the maximum lift coefficient can be increased from 1.5482320 of the original airfoil to 2.1606871,and the stall angle of attack of the airfoil can be increased from original 17 degrees to 20 degrees.Therefore,the new method presented here is believable to improve aircraft landing performance.