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CFD in Support of Flight Testing for Aircraft/Stores Integration

Nunzio Natale, Carlo de Nicola
University of Napoli - Federico II

Alessandro D’Argenio, Pierluigi De Paolis
Aeronautica Militare

This paper discusses the use of CFD in predicting and evaluating the Aerodynamic flow for the integration of a new store.

Determining the flow about an aircraft/store combination can be extremely difficult. Complicated geometry such as pylons, launchers, and internal weapons bays can create severe acoustic and aerothermodynamic environments, which are challenging to numerically simulate. The additional challenge of rapidly and accurately simulating the trajectory of a store separation in a high-volume simulation environment is beyond the capabilities of most CFD programs.

The Italian Air Force Reparto Sperimentale Volo (RSV) is responsible for testing and evaluating aircraft/store compatibility certification. The RSV provides flight certification recommendations, which are based on combinations of engineering analysis, ground and flight testing. Engineering analyses come from disciplines in carriage loads, store separations, flutter, ballistics, stability and control, and electromagnetic compatibility and interference.

Any time a new aircraft is introduced into service, or an old aircraft undergoes substantial modifications or needs to be certified to carry and employ new stores, the store separation engineer is faced with a decision about how much effort will be required to provide an airworthiness certification for the aircraft and stores. Before operational use, all aircraft/store configurations must be certified for safe loading, carriage and jettison/release.

Generally, there are three approaches that have been used: Wind Tunnel Testing, Computational Fluid Dynamics (CFD), analyses and Flight Testing. During the past thirty years there have been considerable advances in all three areas. Nowadays, it is possible to combine these three approaches in a unique process that permits to reduce risks and lowering costs, optimizing the application of ground and flight testing.

The use of CFD can provide time-critical support for engineering analyses - in the form of computed aircraft/store carriage aerodynamic loads, predicted store separation characteristics, and visualized flow field physics - used to optimize the application of ground and flight testing, reducing risk and lowering cost of fielding new weapons.