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

ABSTRACT: This program will address the need for a cost effective way to evaluate unsteady aerodynamic loading on deployed aircraft bay doors so as to allow aircraft designers to evaluate/include them in the early design process. As part of it, we will conduct a wind tunnel demonstration of a"retrofittable"bay door that is integrated with an array of dynamic pressure transducers in order to quantify the unsteady surface loading on it. The door is part of an existing sub-scale weapons bay model representative of the Joint Strike Fighter. In Phase I, the unsteady loading on the doors due to different door scheduling configurations and that due to a store separation event will be studied, but Phase II will extend the mapping to door cycling events and also include structural response studies using Finite-element-modeling (FEM) software such as ABAQUS. The Phase I computational effort will perform simulations of the"empty"weapons bay in various configurations and compare/validate the results using the available experimental data. The proposed hardware and knowledge base will be developed with a"realistic"goal of eventual integration and use by existing air platforms such as the F-35/Joint Strike Fighter (JSF) and J-UCAS. BENEFIT: The proposed program is of direct relevance to the U.S Air Force and its prime contractors responsible for the design of weapons bay doors. The successful measurement and utilization of the unsteady loading data on the bay doors will significantly impact the design cycle via the identification of dangerous tones and undesirable flow field patterns that could trigger large amplitude vibrations in the structure that could lead to fatigue and failure. Details of the dynamic response of a structure to this unsteady loading data on it can be incorporated in to the design process at an early stage and thus help in the design of"better"doors. Also risk assessment studies on varying the door geometry, structure, or any flow control strategy can be easily evaluated using the easily retrofittable design of the weapons bay model. This will be particularly appealing to the U.S Air Force as it can facilitate a"quick"scoping out of the design modifications without full-scale, prototype implementation. This would result in significant cost savings to the U.S Government. At the conclusion of the SBIR effort, the commercialization strategy for CRAFT Tech would involve providing support to the Air Force and its prime contractors in the use of this weapons bay model that will form a test bed for design support as well as for potentially scoping out design modifications. Bay doors are of interest also in wheel wells of aircraft where landing gear is present and this presents an additional avenue for commercialization of the SBIR technology.