A Simplified Approach to Assess Community Noise Levels of Jet Aircraft Using Analytical Tools

Without available direct measurements, the only method of assessing the impact of a completely new aircraft or power-plant design is to utilize a reliable prediction procedure. Such a procedure may be able to make use if a limited amount of directly relevant data, for instance, engine test data, or may have to rely entirely upon empirical component prediction procedures. Traditional aircraft noise prediction procedures based on engine static noise data are generally costly in time, since the engine source separation process is not a straightforward task, demanding several side routines to make it feasible. This paper attempts to present a new and simplified approach to assess community noise levels of a new aircraft design based on static engine noise data. The simplified procedure proposes an alternative to the complete engine source separation process, based on the definition of master parameters like jet noise cut-off frequencies, tonal frequencies and resultant broadband spectra. The process can deal with engine static noise data comprised of both 1/3 OCT and narrowband spectra or only 1/3 OCT band data. Results of community noise predictions based on such a simplified procedure are later compared with those deriving from the traditional procedure.