Jet noise: sound generation by disc and cylinder sources

Detection and Recognition Threshold of Sound Sources in Noise

This study examines detection and recognition thresholds for environmental sounds in the presence of noise, with and without specific expectations about the targets. Human listeners were presented with a selection of everyday sounds masked by noise at initially increasing and later decreasing local signal-to-noise ratios. Participants had to indicate if they either detected or recognized the so...

Lattice-Boltzmann simulation of coaxial jet noise generation

A Lattice-Boltzmann model for high-speed non-isothermal subsonic flows is used to simulate the unsteady jet exhausting from a short-cowl axisymmetric coaxial nozzle and the associated noise. The primary and secondary jet exit Mach numbers are 0.87 and 0.90, respectively, the secondary jet Reynolds number is 2.8 · 10, and the primary to secondary temperature ratio is 2.7. The far-field is comput...

AIAA 2002-0072 POD Analysis of Sound Generation by a Turbulent Jet

Sound Sources

The neareld problem is a source of anxiety with beamforming techniques. We propose a strategy to solve the neareld problem by using a subtractive beamforming technique. The authors earlier proposed a method for noise reduction using paired-microphones. In this paper, the method is improved for neareld sound sources. The proposed method can maintain a high performance regardless of the distance ...

Correlating Noise Sources Identified by Beamforming with Sound Power Measurements (bn0984)

Farfield beamforming is a powerful tool for identifying spatially distributed noise sources. The technique yields an image of the relative sound levels within the measurement aperture. The latest version of the beamforming software is now able to estimate the total power within its measurement aperture. In this work, the noise sources on three types of construction equipment are imaged with a b...