Publications Details

Response of a store with tunable natural frequencies in compressible cavity flow

Wagner, Justin W.; Casper, Katya M.; Beresh, Steven J.; Hunter, Patrick H.; Spillers, Russell W.; Henfling, John F.

Fluid-structure interactions that occur during aircraft internal store carriage were experimentally explored at Mach 0.94 and 1.47 using a generic, aerodynamic store installed in a rectangular cavity having a length-to-depth ratio of 7. Similar to previous studies using a cylindrical store, the aerodynamic store responded to the cavity flow at its natural structural frequencies, and it exhibited a directionally dependent response to cavity resonance. Cavity tones excited the store in the streamwise and wall-normal directions consistently, whereas the spanwise response was much more limited. The store had interchangeable components to vary its natural frequencies by about 10 - 300 Hz. By tuning natural frequencies, mode-matched cases were explored where a prominent cavity tone frequency matched a structural natural frequency of the store. Mode matching produced substantial increases in store vibrations, though the response of the store continued to scale linearly with the dynamic pressure or loading in the bay. Near mode matching frequencies, the response of the store was quite sensitive as changes in cavity tone frequencies of 1% altered store vibrations by as much as a factor of two.