Analysis Of Interior Noise-Control Treatments For High-speed Propeller-Driven Aircraft
An analytical method is described for prediction of the interior noise levels for propeller-driven aircraft, given the exterior noise signature, its harmonic spectrum, and a description of the fuselage sidewall structure and various candidate "add-on" noise-control elements. The structural response is described by the theory of Koval, but simplified to consider the stiffeners as "smeared" elements. The incremental transmission loss (TL) due to add-on noise-control elements is derived from the Beranek and Work method. Comparisons between experimental data and the theory are presented. The method is reasonably accurate below the ring frequency, but is somewhat conservative at the normal incidence angle. This method is, however, expedient computationally, is economical, and permits rapid comparisons of noise-control penalties for various treatment concepts. © 1982 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.