SEA Interior Noise Validation for Rotorcraft

摘要

Rotorcraft interior design to meet internal noise specifications could greatly benefit from improved predictive methodologies. Traditionally, interior design for rotorcraft has been experimentally derived from trial and error. This process, however, has its limitations due to untimely testing after the aircraft has finished the design process. Finite element methods (FEM) and boundary element methods (BEM) are a step forward to the predicting the internal acoustics noise of the rotorcraft. However, these methods are limited to low to mid frequency solutions. Statistical Energy Analysis (SEA) is a recently matured method that is designed to be effectively used in the development of interior treatments at the mid to high frequencies where rotorcraft noise is most predominant. SEA can be used to optimize acoustic treatments with respect to performance, weight, and cost. However, the determinations of the acoustic source power inputs, which are required for SEA, are difficult to obtain. The dominant power inputs causing helicopter internal noise include gear clash power emanating from the main gearbox and overpressures on the fuselage from the main and tail rotors. The intent of this paper is to show how these power inputs can be quickly and efficiently derived from testing of similar aircraft. Furthermore, this paper will show how the SEA solution can be used to optimize a rotorcraft interior treatment.