Radiative Transfer Calculations on Hybrid Unstructured/Structured Flowfield Grids

The field of CFD has witnessed dramatic maturation of unstructured, hybrid multi-element technology, along with implementation of such simulation methodology on large-scale multi-processor parallel, computational architecture. Absence of equivalent forradiative transfer simulations limits design or threat-oriented infra-red (IR) signature analyses to single CPU simulations on structured grids. The present proposal is focused on rectification of this limitation by undertaking he systematic developmentand validation of a novel unstructured grid technique for conducting radiative transfer simulations. The model will employ hybrid multi-element grids and operate in multi-CPU, parallel processor computational environment. The ability to perform localizedmesh adaption is a key feature of the new unstructured grid IR methodology. The developmental activities of the SBIR program will be accompanied by systematic validation against industry-standard IR methodology, using identical physical models (bandmodels, atmospheric transmission models and scattering models). The overall capabilities of the novel unstructured radiative transfer methodology will be demonstrated by performing IR signature predictions for a wide-range of scenarios, e.g. tacticalmissile, threat ballistic missiles (TBM), divert jets on hypersonic interceptors, etc. Application to aircraft and rotorcraft plume flowfields will also be conducted to assess geometrical versatility and overall fidelity of the new technique. Thetechnology development proposed is of direct relevance to Boost Phase Intercept (BPI) and will aid in assessing the potential of innovative hardware technology developments proposed for space and sea-based kinetic energy BPI concepts. The IR capabilitydevelopment is also of direct relevance to other major DoD initiatives of current relevance, e.g. Joint Strike Fighter (JSF), Unmanned Combat Air Vehicle (UCAV), V-22 Opsrey, etc. For commercial dual-use applications, this technology is directlyapplicable to remote sensing of the atmosphere for weather modeling and prediction, environmental studies of the earth, pollution monitoring, ocean temperature, etc.