Hypervelocity Aerodynamic Interaction of Ballistic Bodies

The process of dispensing unguided submunition projectiles from weapons systems must result in stable projectile flight with high kinetic energy and even dispersion over the target area. This project will incorporate a solid body collision methodology into the existing Loci/CHEM coupled 6-DoF/CFD framework to enable simulation of the simultaneous collision and aerodynamic interference effects between large numbers of projectiles that dominate the early phases of the ejection process that are not amenable to simulation with engineering level methods. The Loci/CHEM architecture has demonstrated extreme scalability and automatic parallelism that make a CFD based simulation approach with large numbers of moving bodies possible. Phase I will demonstrate the efficiency of the CFD based simulation system, integrate a body collision prediction module in the coupled 6-DoF/CFD system, and demonstrate the scalability to simulations with large numbers of projectiles. Phase II will see full implementation of the coupled simulation capability, application demonstrations for capturing dominant influence factors in the dispersion process, and development of a design-of-experiment methodology to deliver probabilistic projectile state definitions with reasonable computational effort. The resulting probabilistic definition of projectile spatial distribution and flight state will be handed over to the more economical engineering level methods for the terminal flight phase. BENEFIT: Military Application: The resulting simulation capability will enable design and evaluation of technology and concept maturation for save dispensing and pin-point delivery of payloads. It will support integration design of submunition and ordnance ejection processes for hypersonic and lower Mach airframes. Commercial Application: The predictive capabilities will benefit system design and process planning for air delivery of payloads such as humanitarian relief supplies. The methodology will help predict payload ground-impact distributions for flight regimes intended for commercial applications.