The present investigation was conducted to evaluate some approximate methods for the prediction of shielding of monochromatic sound and broadband noise by aircraft components. The approach was to make anechoic-chamber measurements of the shielding of a point source by various simple geometric shapes, and to then compare the measured values with those calculated by the superposition of asymptotic closed-form solutions for the shielding by a semi-infinite plane barrier.nThe shields used in the measurements consisted of rectangular plates, a circular cylinder, and a rectangular plate attached to the cylinder to simulate a wing-body combination. The normalized frequency, defined as a product of the acoustic wave number and either the plate width or cylinder diameter, ranged from 4.6 to 114.
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