Rotorcraft noise model (RNM) and acoustic repropagation technique (ART2) validation and application using CH‐146 (Bell 412) measurement data Free

A series of acoustic measurements were conducted at Moose Jaw Canadian Forces Base, Saskatchewan, Canada in June, 1998 for obtaining detailed noise data on a large array of ground‐ and crane‐based microphones for a CH‐146 helicopter. The project, conducted by the North Atlantic Treaty Organization (NATO) Committee on the Challenges of Modern Society was to define test procedures and analysis methods for the standardization of a NATO rotorcraft noise database. Four independent microphone arrays were deployed by the USAF, NASA, RAF, and DERA. Data from the USAF and NASA arrays were used to validate the Rotorcraft Noise Model (RNM). USAF data were processed via an updated acoustic repropagation technique (ART2) to define the rotorcraft broadband sound hemispheres. The source noise was then propagated to the measurement locations using RNM. Agreement with the original USAF measurements demonstrated consistency of the ART/RNM process. Agreement with the independent NASA measurements provided validation of the RNM as a prediction tool.