Combining asynchronous microphone array measurements for enhanced acoustic imaging and volumetric source mapping

This paper explores the advantages of combining asynchronous microphone array measurements for acoustic source mapping in two and three–dimensional applications. Four different approaches are considered, three consisting of the combination of the source maps (arithmetic mean, geometric mean, and minimum value), and a fourth one obtained by...

Experimental study of realistic low–noise technologies applied to a full–scale nose landing gear

The landing gear system is the dominant airframe noise source for most modern commercial aircraft during approach. This manuscript reports the results from the ALLEGRA (Advanced Low Noise Landing (Main and Nose) Gear for Regional Aircraft) project. This project assessed the performance of several highly realistic low–noise technologies (LNTs)...

Acoustic Imaging and Spectral Analysis for Assessing UAV Noise

With increasing UAV operations, tailored measures need to be implemented to integrate the massive employment of these vehicles in day-to-day operations. One of the current issues of UAVs is the noise emitted by these vehicles. The purpose of this research is to offer a doorway towards understanding the behavior of drone noise with changing...

Assessment of the use of global optimisation techniques for aircraft noise source identification

Over the past years, noise nuisance around airports strongly increased resulting in the need for aircraft noise reduction. Therefore, the noise sources should be known. This thesis assesses a new acoustic imaging method to identify sources on aircraft fly-over measurements. The proposed Global Optimisation (GO) algorithm is based on the theory...

Integration methods for distributed sound sources

Most acoustic imaging methods assume the presence of point sound sources and, hence, may fail to correctly estimate the sound emissions of distributed sound sources, such as trailing-edge noise. In this contribution, three integration techniques are suggested to overcome this issue based on models considering a single point source, a line...

Microphone arrays for imaging of aerospace noise sources

With the continuous growth in demand for air traffic and wind turbines, the noise emissions they generate are becoming an increasingly important issue. To reduce their noise levels, it is essential to obtain accurate information about all the sound sources present. Phased microphone arrays and acoustic imaging methods allow for the estimation of...