Semi-Empirical Aerodynamic Model and Design Tool for the Development of Fixed and Free Rotating Wrap Around Missile Tail Configurations

摘要

The Wrap Around Fin (WAF) is a common configuration for rocket or ground to ground missile tails. The WAF, is common when the space in the launcher is limited. Moreover, a free rotating tail allows for canard control in roll by eliminating the effect of roll reversal. The combination of these two reasons leads to design of freely rotating wrap around fins. This relatively complicated configuration has particular aerodynamic properties, characterized by coupling between the different flight planes. The goal of the present work is to propose a simple and computationally-effective design tool of a rotating or a fixed WAF. This tool is based on a semi-empirical aerodynamic model, based on relatively simple assumptions that try to describe the wrap-around fins aerodynamics. This model is able to describe the main aerodynamic phenomena expected, and allows for the calculation of the rotating velocity, in the case of a free rotating tail. The validation of the model was performed by comparison with experimental results. A series of experimental measurements on a rocket in a wind tunnel with fixed and free rotating tail configurations is presented. The semi-empirical model calculations describes, qualitatively at least, the main aerodynamic phenomena measured in the experiments.