Dynamic Stability Numerical And Experimental Research For A Missile Configuration With Strake Wings

The research and exploration of stability play a important role in aircraft design. The flow field present strongly nonlinear and unsteady flighting modern aircraft in high angles of attack(AOA) and large angular rate, in which offen there will be a complicated aerodynamic phenomenon. Rock is a induced oscillation of aircraft in roll, which is a representative flow/motion coupling phenomenon. Rock will effect the flight security and accomplishment of missions. A missle configuration wit h strake wings studyed in this paper typically. There aim to develope a coupling compucational method between aerodynamics and flight mechanics, combining with high speed wind tunnel free-to-roll tests to analyze the affect of strake configurations on the rock motions, and recognize the flow/motion coupling property, and then to reveal the mechanism that leads to rock.A numerical simulation methodology based on unsteady RANS equations and 6-dof flight mechanic equations are developed and applied. Flow slover is a finitevolume solver of structure grid with dual time stepping and S-A one equatio n turbulence model. Adams prediction-correction method is used to couple the aerodynamic and flight mechanic comput ations which also can improve the accuracy of unsteady compucation. This methodology are validated through lots o f test cases, and results show the program have considerable accuracy and stabilit y. The free-to-roll tests of strake missle have complished in the FL-24 wind tunnel, It is going to clear the rock motion. A PIV test have complished in FL-21 wind tunnel, which show that there exist extremly great complex vortexes structure in the strake missle flow when a larger AOA.Numerical caclulations about staic and free-to-roll are conducted for strake missle. Results show that the wingward strake vortexes significantly affect the leeward dins which is the most important factor lead to a loss in roll damping. The position of strakes affect the altitude of the strake vortexes, and then affect the interference between the strake vortexes and tail fins. The effect between the interlaced wings and strakes also can make model enter into LCO under some certain conditions. The computations have good agreement with the wind tunnnel test. Workes in this paper have developed a method to study dynamic stabilit y for complex aircraft in three dimensional, indicated the rock motion and mechanism o f strake missle, which is valued to surpress or eliminate rock motions through configuration optimization in engineering.