Project Description

This project investigates the aerodynamic behavior of the  Javelin missile's tail fin control system using ANSYS Discovery CFD simulation. The study focuses on how tail fin deflection angles influence the three-dimensional force distribution on the missile body and the resulting Flight Path Deviation.

Objectives

This project aims to perform a parametric CFD study on the Javelin missile tail control fins by varying the deflection angle from 0° to 25° and extracting the three-dimensional force components at cruise velocity. The resultant lateral force, missile deflection angle (θ), and directional angle (φ) are then calculated to evaluate how fin deflection translates into actual flight path deviation. Ultimately, the study seeks to identify the aerodynamic stall onset point and define the optimal deflection range that delivers maximum control authority without loss of aerodynamic stability.

Results and Discussion

The parametric CFD simulation revealed three distinct behavioral phases as the tail fin deflection angle increased from 0° to 25°. In the linear phase (3°–11°), the lateral control force grew rapidly at a rate of approximately 4–6 N per degree of fin deflection, indicating fully attached flow and highly efficient aerodynamic control. Beyond 11°, the growth rate slowed significantly, marking the onset of the saturation phase where θ peaked at 44.8° and Flateral reached its maximum of 107 N at 17°. Post-stall instability then emerged beyond 19°, where both parameters fluctuated unpredictably while drag nearly doubled from 65 N to 128 N.