Computational Modeling of Geometrically-Complex Weapons Bays

A computational study of the weapons bay acoustics characteristics on a geometry representative of the F-35 is currently underway to support the development of possible "control" strategies for the reduction of dynamic pressure loads in the weapons bay. Initial computations evaluate the wind-tunnel model design and establish a baseline of what is expected during the wind-tunnel testing. Computational fluid dynamics (CFD) simulations and wind-tunnel tests on the 1/20th scale model at Mach 1.5 have demonstrated that leading-edge mass blowing combined with leading-edge shape modification as a control strategy provides significant reduction of ~4-5 dB were shown over the entire bay, with some regions showing reductions as high as 10 dB. Furthermore, the introduction of control via blowing resulted in no locations where there was any augmentation of noise levels. The CFD not only guided the wind-tunnel testing, it was also able to significantly improve the understanding of the complex flow field associated with the geometrically-complex weapons bay. The importance of the bay leading-edge geometry and the outboard door interaction with the shear layer are evident from the computational results.