VORTEX STUDY OF FLOW OVER AIRFOIL WITH GURNEY FLAP AND NUMERICAL ANALYSIS OF ITS DRAG CHARECTERISTICS FOR DIFFERENT ARRANGEMENTS

摘要

The high-lift performance of an aircraft largely effects it's economic viability. An effective high-lift capacity of aircraft allows greater payloads, less fuel consumption and longer range for given gross weight. Generation of increased lift also allows steeper take-off ascent which can reduce the required size of runway. Mechanically simple high-lift devices are easier to manufacture and minimize manufacturing and maintenance costs, thus increasing profitability. Gurney flap is one such mechanically simple high-lift device. A Gurney flap is a flat plate of the order of 'some small percentage' of the aerofoil chord in length, generally oriented at right angle to the chord line of the aerofoil. The two-dimensional aerodynamic performance of the Gurney flap is characterized by means of computational fluid dynamics. Simulations are carried out on a NACA 4412 airfoil equipped with Gurney flap and effects of flap size, mounting angle and mounting position on airfoil performance are investigated. This author recommends that a Gurney flap of 2% chord length should be installed at the trailing edge perpendicular to the chord of the airfoil.