Development and Validation of a Computational Tool for Missile Flight Through Rain

The CFDRC team proposed to develop and validate a first-principles based, high-fidelity multiphase CFD tool to predict raindrop distortion and demise in the flow field around a missile in supersonic flight in order to understand both the impact event and the associated material damage mechanisms. In Phase I, the distortion of spherical drops in a planar shock front case showed excellent agreement with experimental measurements. Phase II efforts will fully develop and enhance our VOF-based solution methodology. The new development effort includes adaptive mesh refinement, the comprehensive capability of heat transfer and phase change effect on the drop demise, droplet compressibility, and supercooling. Experiments will be conducted in parallel to characterize the drop shape at terminal velocity. The raindrop distortion with a planar shock wave and flow field in front of a traveling projectile will be experimentally measured. The data will be further used for validation and refinement of the VOF solver. The time-dependent shape of multiple drops as they travel the atmospheric flow field around a missile in supersonic flight will be studied. The effect of angle of incidence, the post-shock, vehicle flow field, and droplet demise will be investigated and impact pressure on the missile will be analyzed.