Aeromechanic Analysis of a Missile with Freely Spinning Tailfins

The objective of the present work is to demonstrate the utility of Chimera overset grid methods for missiles with freely spinning tailfins. Computations on grids with two levels of resolution and three levels of geometric detail are used to assess grid convergence and the significance of the different geometric features of the missile. The grid convergence is good for overall force and moment vectors. The numerous protuberances on the missile have a limited influence on the overall forces. A yaw maneuver is computed on a medium resolution grid with 17 million gridpoints. The tail spins in response to the computed tail rolling moment. The asymmetric inflow to the tail results in a spin-rate of approximately 2000 revolutions per minute. The results are in excellent agreement with an unstructured grid CFD model, and in fair agreement with experimental results. Overall, the Chimera overset method seems to be well suited for geometrically complex moving body configurations.