The Aerodynamic Characterristics Of The Grid Fin Drag Reduction Research

The grid fin is a new wing consists of many thin grid walls mosaiced in a border. It’s structure characteristics are small size, chord short, light weight, high strength quality, easy to fold, aerodynamic advantages are small hinge moment, big stall angle of attack, good lift characteristic. Especially, in great angle of attack and high mach number the lift characteristcs is better than flat wing. It could be used as stabilizing fin and also be used as ful-motion style canard in guided weapon. However, it’s big drag seriously influence it’s extensive use in the field of aerospace. This article was aimed at the research of leading edges swept grid fins in drag reduction and reduction mechanism, and it was studied by numerical simulation and wind tunnel tests.In the light of the lift-drag characteristic of different leading edge swept angle grid in subsonic, transonic and supersonic developed numerical simulation. Analysis the leading edge sweep angle grid flow characteristics though nephogram. The results showed that leading edges swept grid fin could improve flow chocking phenomenon in high subsonic, and could obviously reduce the wave drag. In the same mach number, the grater the sweep angle, the smaller the drag. The differences of the sweep angle have great effect on the lift-to-drag ratio in the entire mach number range. The lift-to-drag ratio is increased with the sweep angle.In the light of the grid fin swept back assembly model developed wind tunnel test research and got the aerodynamic characteristics at supersonic speeds studied, including drag force coefficient, lift force coefficient, lift-to-drag ratio. Analysis about the aerodynamic characteristics derivative with the mach number and angle of attack were got. Wind tunnel test results showed that leading edges swept grid fin could reduce the wave drag obviously, and the greater the sweep angle, the smaller the drag of grid fin. Throughout the entire mach number range,the lift-to-drag ratio is increased with the sweep angle.All the research demonstrate that grid fins swept back locally can obviously reduce the wave drag, and increase the lift-to drag ratio. This is an effective way to reduce drag and increase lift of grid fins.