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

The survivability of tactical missiles through adverse weather is difficult to predict, because of the dependency on many variables and the unpredictable nature of weather. This proposal is focused on an effort to develop and test a physics-based methodology for the prediction of the droplet distortion and demise in the flow field around missiles in supersonic flight. Our technical approach of Phase I is to first validate our baseline Volume-Of-Fluid (VOF) based solution methodology for the multiphase flow of a single raindrop in supersonic flow using the experimental conditions of Theofanous et al. Controlled laboratory experiments will be conducted in parallel to fully validate the solution technology. The time-dependent shape of multiple drops as they traverse the atmospheric flow field around a missile in high-speed flight will be conducted. Post-shock vehicle flow field and droplet demise will be investigated and impact pressure on the missile will be analyzed. A grid adaptive methodology will be designed and demonstrated to increase fidelity and improve efficiency. Phase II will fully develop the VOF solver and adaptive grid capability. A parametric computational study for representative conditions with hemispheric and aerodynamic missile forebodies will be conducted, and experiments will be designed to validate the predictions.