Spike-Nosed Projectiles: Computations and Dual Flow Modes in Supersonic Flight

摘要

This study was made to assess the capability of a Computational Fluid Dynamic(CFD) method to adequately determine the aerodynamic coefficients for the unusual configurations of sharp-edged, spike-nosed projectiles that are of interest to the US Army. McCormack's time-dependent, explicit scheme was used for the full Navier-Stokes equations in a zonal gridding topology. Three configurations were computed at Mach = 1.72 and zero angle of attack. The results are compared against wind tunnel data. The flow fields computed are in qualitative agreement with wind tunnel schlieren photographs, and the computed drag coefficients are within two percent of the wind tunnel measurements. Two important issues are faced: (1) the always existing possibility of a dual flow mode and which one will occur under specific flow conditions; and (2) observed role of the turbulence level and numerical model in affecting flow separation and, thus, influencing a particular flow mode to be predicted. This study demonstrates the successful application of the present approach to these unusual configurations and, thus, leads the way to further application for more complex configurations, such as those with booms and fins. Keywords: Aerodynamic characteristics; Projectile nose/spikes; Bluntbodies; Supersonic characteristics. (RWJ)