Prediction of the Pressure Oscillations in Cavities Exposed to Aerodynamic Flow
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Cavities, or rectangular cutouts, exposed to fluid flow can produce an intense aero-acoustic environment. Past experience has show that severe fluctuating pressures exist in open aircraft weapon bays under certain flight conditions. The aircraft designer must be able to predict the fluctuating pressure environment of cavities in order to assess the effects on the internally carried stores or near-by structure. Prediction methods were formulated based primarily on data from flight tests on cavities with length-to-depth-ratios of 4, 5 and 7 over a Mach number range of 0.6 to 1.30. Available data in the literature were used to extend the range of application of the prediction method to cavities with length to depth ratios from 2 to 7 and for Mach numbers from 0.5 to 3.0.
The prediction method enables designers to estimate the (1) modal frequencies, (2) modal frequency amplitudes, (3) broadband amplitudes, (4) length-to-depth effect, (5) Mach number effect, and (6) the longitudinal distribution of the fluctuating pressures in the cavity.
D.L. Smith; L.L. Shaw