Aerodynamic evaluation of blunted conic shaped war head nose geometries for transonic flow conditions

The aerodynamic shape optimization is performed to improve aerodynamic performance by changing missile geometry and to investigate the effects of shape optimization on missile performance at transonic speeds. Under the specified constraints, missile model shape change is numerically investigated to decrease aerodynamic drag coefficient. For spherical blunted conic shaped warhead nose cone missile models, the effects of nose cone length, missile diameter, missile length and Mach number are analyzed in terms of drag and moment coefficient. Different missile shapes are created using 4-Parameter Box Behnken Design of Experiments (DOE) method and the nose cone optimization study is performed using Response Surface Methodology (RSM). 25 different missile designs were analyzed under zero angle of attack. Steady state turbulent flow fields around this missile are calculated by solving Reynolds Averaged Navier-Stokes equations. Spalart-Allmaras turbulence model with extended wall function is used to calculate turbulent viscosity. It is observed that there are some cases where drag and moment coefficient values change significantly. Moreover, it has been observed that these four parameters have a significant effect on the formation and properties of the shock wave. The Response Surface Method is used to optimize the missile geometry. Optimization results show that the aerodynamic performance of the missile is improved by approximately 54% over the baseline model and 8% over the lowest drag coefficient case obtained from the experimental design.