Research On The Aerodynamic Characteristics Of The Projectile With Wrap Around Fins

Wrap around fin(WAF) is used very widely on weapons in modern times due to its advantages of saving room,being convenient for packing and so on. The flying stability of the unguided projectile with wrap around fins could be influenced by the self-induced rolling characteristics and the cross coupling effects of the WAF badly. It is necessary to study further on this special aerodynamic problems.The aerodynamic characteristics of a projectile with wrap around fins are studied systematically in this paper, as follows:1. The lift coefficients,drag force coefficients,pitch moment coefficients,pitch damping moment derivatives and roll damping moment derivatives are obtained from engineering calculation through looking wrap around fins as flat fins of the same projection aera.2. The transonic flow field solutions of a TTCP standard WAF-body combinations are computed using the software of CFD, the results are agreement with experiment dates, this verifies that the accuracy of the numerical simulation model is ensured.3. The static aerodynamic characteristics of the projectile are computed using the software of CFD, the results of the numerical simulation are agreement with the engineering calculation, this verifies that the results of the static aerodynamic characteristics of WAF from engineering calculation are satisfactory.4. After the airdrop experiments of the system of the projectile and speed-down parachute, the balance velocity obtained from the optics apparatus on the ground,the balance spinning speed obtained from the gyroscope on the projectile and the image obtained from the infrared detector on the projectile are all used to simulate the six-dimension exterior trajectory of the projectile and identify the roll damping moment derivatives, and the identification can safely come to a conclusion that the absolute value of roll damping moment derivatives from the engineering calculation are on the low side.5. The instable phenomenons of the projectile in the airdrop experiments are analyzed and...