Aircraft noise

About: Aircraft noise is a research topic. Over the lifetime, 3051 publications have been published within this topic receiving 32039 citations.

Community annoyance from aircraft and ground vehicle noise

Abstract: Data from published noise‐annoyance surveys are related to a common measure of noise exposure Ldn. The results provide means for predicting the annoyance (experienced by percentages of people of normal and of supersensitivity) attributable to noise from aircraft and from street and road traffic. Correlations of 0.90 to 0.95 are found between Ldn and percentages of people annoyed by aircraft noise when low, moderate, and higher levels of annoyance are measured for both a broad range (35 dB) and a restricted range (20 dB) of Ldn. Noise from urban street and road traffic is shown to cause less annoyance than the noise from aircrafts when both have the same Ldn as typically measured or estimated for outdoors. The difference, equivalent to a difference of about 10 dB in Ldn, is attributed to acoustical factors that diminish in‐and‐around‐the‐home noise dosages from ground vehicular traffic compared to dosages from aircraft operations. Generalized functions showing degrees of annoyance and percentages of U.S. u...

Birds living near airports advance their dawn chorus and reduce overlap with aircraft noise

Abstract: Anthropogenic noise is a major pollutant for organisms that live in urban areas. City birds modify their songs in ways that can increase their communication potential in spite of noise. However, these changes cannot prevent song masking by the extremely loud noises to which some urban bird populations are exposed. Here, we show that birds near a major airport advance their dawn singing time, thus reducing overlap with periods of intense aircraft noise. This modification was stronger in species whose normal singing time was relatively late, those which overlapped the most with aircraft noise. Although suggestive of a causal relationship, this pattern does not allow us to tell apart the effect of aircraft noise from that of other variables that may correlate with dawn singing time. In order to control for such potentially confounding variables, we replicated the study in several airports at different latitudes in Spain and Germany. The results show that indeed the overlap of song chorus with aircraft noise was the key factor that influenced time advancement. Aircraft traffic time was the main predictor of song advancement: across Europe, those bird populations whose singing time overlapped the most with aircraft traffic were those that advanced their song timing to a higher extent. Our results exemplify how behavioral plasticity may allow the survival of avian populations in areas of high noise pollution. However, such an adaptation likely involves departing from optimal singing times, leading to higher energetic costs and amplifying between-species differences in competitive ability and resilience.

Jet-Surface Interaction Test: Far-Field Noise Results

Abstract: Many configurations proposed for the next generation of aircraft rely on the wing or other aircraft surfaces to shield the engine noise from the observers on the ground. However, the ability to predict the shielding effect and any new noise sources that arise from the high-speed jet flow interacting with a hard surface is currently limited. Furthermore, quality experimental data from jets with surfaces nearby suitable for developing and validating noise prediction methods are usually tied to a particular vehicle concept and, therefore, very complicated. The Jet/Surface Interaction Test was intended to supply a high quality set of data covering a wide range of surface geometries and positions and jet flows to researchers developing aircraft noise prediction tools. During phase one, the goal was to measure the noise of a jet near a simple planar surface while varying the surface length and location in order to: (1) validate noise prediction schemes when the surface is acting only as a jet noise shield and when the jet/surface interaction is creating additional noise, and (2) determine regions of interest for more detailed tests in phase two. To meet these phase one objectives, a flat plate was mounted on a two-axis traverse in two distinct configurations: (1) as a shield between the jet and the observer (microphone array) and (2) as a reflecting surface on the opposite side of the jet from the observer. The surface was moved through axial positions 2 ≤ xTE/Dj ≤ 20 (measured at the surface trailing edge, xTE, and normalized by the jet diameter, Dj) and radial positions 1 ≤ h/Dj ≤ 20. Far-field and phased array noise data were acquired at each combination of axial and radial surface location using two nozzles and at 8 different jet exit conditions across several flow regimes (subsonic cold, subsonic hot, underexpanded, ideally expanded, and overexpanded supersonic cold). The far-field noise results, discussed here, show where the surface shields some of the jet noise and, depending on the location of the surface and the observer, where scrubbing and trailing edge noise sources are created as a surface extends downstream and approaches the jet plume.