Aerodynamic Analysis of Deployed Bay Doors on Modern High-Speed Aircraft

ABSTRACT: The need for evaluation of aerodynamic loads on internal weapons bay doors comes from the US Air Force's requirement to open doors on many of its aircraft during flight. This ranges from an aircraft's low-speed opening of landing gear doors and speed brakes to opening weapons bay doors in supersonic flight. This sets up a situation for unsteady aerodynamic loading of these surfaces due to the potential for unsteady flow oscillations in and around the exposed bay that is known to exhibit strong tonal content under many of the flight conditions at which the U.S. Air Force operates its aircraft. These weapons bay tones and the oscillatory nature of the separated flow on the doors have the potential to excite structural modes of the doors, aircraft surfaces, or externally carried munitions and fuel tanks and can lead to buffet, flutter, or fatigue induced failures. Part of the aircraft flight certification for all operational and developmental aircraft includes assessments of the aircraft store compatibility, which is made more difficult in view of the fluid structure interactions that must be taken into account. During an aircraft development and demonstration program, a validated Fluid Structure Interaction (FSI) model provides a means of generating data to support assessments regarding the design of the structure, provide flight certification, etc. BENEFIT: A high-fidelity Unified Fluid Structure Interaction (FSI) Modeling and Testing capability for evaluation of dynamic loads on payload bay doors will result from the SBIR program. CRAFT Tech will market this unique capability to prime contractors and manufacturers of large commercial airliners/military transports/bombers and tactical fighter to study loads on weapons bay doors, the wheel bay doors and other near vicinity surfaces/components. This technology is obviously relevant to small passenger and/or regional jets, as well for loads associated with wheel wells, etc. The SBIR product is well-suited for supporting the design of a new generation of launch vehicles that is placing a premium on robust and accurate predictions of aero-acoustic and buffet loads experienced at launch. They are also very applicable to large-scale commercial pumps that are extremely prone to performance loss and/or structural failure caused by cavitation-induced severe dynamic loading.