http://worldcat.org/entity/work/id/137445656

Fluctuating Pressure Loads for Hypersonic Vehicle Structures. Phase 1

This investigation was conducted to determine the ability to predict acoustic loads on supersonic/hypersonic structures with attached and separated flows. These techniques, which are based on laws governing boundary layer flow and shock physics, provide scaling parameters to extrapolate ground test results to flight conditions and can be used for the design process. It was determined that efficient, thin aerodynamic control surfaces generally produce weak shock/ boundary layers interactions where the rms pressure levels are not significantly augmented over attached flow levels. The exception to these findings include: (1) corner flow (inlet and stabilizers); (2) bow shock interaction (inlet and stabilizer); and (3) shock on shock/boundary layer (cowl/inlet, bow shock/inlet, and bow/inlet/cowl). Other potential interactions that may cause problems have been identified as: (1) axial offset (non-common intersection of two planes); (2) shock interaction with laminar boundary layers; (3) angle of attack effects; and (4) viscous approach flow along ramp leading to the inlet. An experimental program is recommended to address these issues; in particular for M> 3 where acoustic data does not exist. These experiments should be conducted in a facility that allows for preliminary test runs to ensure desired results. The WRDC Mach 3 and Mach 12 facilities are recommended for a Phase II investigation. Results of the Phase I and II efforts will provide the ability to design structures subject to complex flow interactions such as the National AeroSpace Plane.

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