Computational Fluid Dynamics Capability for Internally Carried Store Separation

Abstract
The ability to predict safe and effective release of air-launched weapons carried internally in a weapon bay or externally on a pylon/rack is required by the Safety Committee before approval is given for a flight test to validate various store separation characterisitics. Because of the novel conditions attendant to test and evaluation (T and E) testing, only limited experimental and flight data are available beforehand to aid in assessing safe weapon release. Computational methods have the potential of resolving, in a timely manner, the store separation problem without these weaknesses. Two areas need to be addressed. First, an accurate computational algorithm is needed to minimize numerical uncertainty as the store is tracked in time. Second, correct physical models must be implemented to model the moving store, including grid capability to provide accurate numerical flowfield predictions for situation of weapon carriage and release from an internal weapons bay. Based on a truly multidimensional unrestricted Essentially Non-oscillatory (ENO) scheme, a new UNIVERSE (Unification of essentially Non-oscillatory Interpolation techniques with a geometrically VERSatilE) series code has been developed at the Rockwell International Science Center. The new ENO concepts are state-of-the-art interpolation schemes that work with arbitrary cell shapes. For example, hexahedral, triangular prism, and tetrahedral elements (conservation cells) can all be covered in a unified manner. This also implies that both structured and unstructured bookkeeping schemes can be employed to conveniently treat complex topologies. A new suite of fully automatic flexible-cell mesh generation methods is also being developed for integration with the new series.