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Concept: Aircraft noise


While noise annoyance has become recognized as an important environmental stressor, its association to mental health has hardly been studied. We therefore determined the association of noise annoyance to anxiety and depression and explored the contribution of diverse environmental sources to overall noise annoyance.

Concepts: Anxiety, Psychology, The Association, Noise pollution, Sunshine pop, Aircraft noise


The largest study until now around 6 major European airports, the HYENA (HYpertension and Exposure to Noise near Airports) study, reported an excess risk of hypertension related to long-term aircraft noise exposure. The DEBATS (Discussion on the health effects of aircraft noise) study investigated the relationship between this exposure and the risk of hypertension in men and in women near French airports.

Concepts: European Union, Immigration, French language, France, Noise pollution, Aircraft noise


Environmental noise exposure disturbs sleep and impairs recuperation, and may contribute to the increased risk for (cardiovascular) disease. Noise policy and regulation are usually based on average responses despite potentially large inter-individual differences in the effects of traffic noise on sleep. In this analysis, we investigated what percentage of the total variance in noise-induced awakening reactions can be explained by stable inter-individual differences.

Concepts: Noise pollution, Aircraft noise


Air traffic has increased for the past decades and is forecasted to continue to grow. Noise due to current airport operations can impair the physical and psychological well-being of airport residents.

Concepts: Airport, Noise pollution, Aircraft noise


The aim of this study was to investigate the influential power of a celebrity to convey key safety messages in commercial aviation using a pre-flight safety briefing video. In addition, the present research sought to examine the effectiveness of subtitles in aiding the recall of these important messages as well as how in-cabin aircraft noise affects recall of this information. 101 participants were randomly divided into four groups (no noise without subtitles, no noise with subtitles, noise without subtitles, and noise with subtitles) and following exposure to a pre-recorded pre-flight safety briefing video were tested for recall of key safety messages within that video. Participants who recognised and recalled the name of the celebrity in the safety briefing video recalled significantly more of the messages than participants who did not recognise the celebrity. Subtitles were also found to be effective, however only in the presence of representative in-cabin aircraft noise.

Concepts: Present, Effect, Effectiveness, Noise pollution, Recall election, Aircraft, Celebrity, Aircraft noise


Assessment of aircraft noise is an important task of nowadays airports in order to fight environmental noise pollution given the recent discoveries on the exposure negative effects on human health. Noise monitoring and estimation around airports mostly use aircraft noise signals only for computing statistical indicators and depends on additional data sources so as to determine required inputs such as the aircraft class responsible for noise pollution. In this sense, the noise monitoring and estimation systems have been tried to improve by creating methods for obtaining more information from aircraft noise signals, especially real-time aircraft class recognition. Consequently, this paper proposes a multilayer neural-fuzzy model for aircraft class recognition based on take-off noise signal segmentation. It uses a fuzzy inference system to build a final response for each class p based on the aggregation of K parallel neural networks outputs Op(k) with respect to Linear Predictive Coding (LPC) features extracted from K adjacent signal segments. Based on extensive experiments over two databases with real-time take-off noise measurements, the proposed model performs better than other methods in literature, particularly when aircraft classes are strongly correlated to each other. A new strictly cross-checked database is introduced including more complex classes and real-time take-off noise measurements from modern aircrafts. The new model is at least 5% more accurate with respect to previous database and successfully classifies 87% of measurements in the new database.

Concepts: Signal processing, Pollution, Light pollution, Noise pollution, Flight, Fixed-wing aircraft, Aircraft, Aircraft noise


Regulatory agencies often define strict, decibel-denominated thresholds of significance of noise impacts to protect some fraction of the residential population from exposure to highly annoying noise. Definitions of the “significance” of aircraft noise impacts and recommendations of land use “compatibility,” however, typically lack detailed, systematic rationales. Instead, the definitions are justified by reference to decades-old policies that were adopted without benefit of modern understandings of noise-induced annoyance, by appeals to authority, and by generic citations of non-peer reviewed documents. Although regulatory policy decisions may properly take into consideration political and economic consequences, aspects of them are amenable to logical formalization. In particular, advances in understanding of community reaction to transportation noise now permit a systematic rationale for aircraft noise regulation. The current analyses show how regulatory policy positions can be derived from two parameters: (1) the minimal percentage of the population of a nominally average community to be protected from exposure to highly annoying noise; and (2) the percentage of all communities to which this degree of protection is intended to apply. Together with a reliable dosage-response relationship, these two parameters permit quantitatively justifiable definitions of significant noise impact.

Concepts: Definition, Extensional definition, Law, Policy, Protection, Noise pollution, Aircraft noise, Noise regulation


The noise levels generated by tactical aircraft pose health hazards to personnel working in the vicinity of the aircraft (such as on an aircraft carrier deck) and are annoying to communities close to airbases. The engine exhausts are hot and supersonic and generally operate in an off-design condition, where the nozzle exit and ambient pressures are unequal. This results in shock cells in the jet plume. The interaction between the jet turbulence and the shock cells generates broadband shock-associated noise. The dominant noise radiation is in the downstream direction and is associated with the supersonic convection of turbulence in the jet. This paper describes the development of a technology to reduce both noise sources and involves the controlled injection of air into the diverging section of the nozzle to generate flow corrugations. This enables the jet to operate closer to its design condition and also breaks up the large scale turbulent structures that are responsible for the dominant noise radiation. Both flow and acoustic measurements are described. In addition, steady RANS computations provide information on the flow upstream of the nozzle exit and the effect of injector operating conditions on the flow field. Estimates of nozzle performance are also described.

Concepts: Fundamental physics concepts, Fluid dynamics, Noise pollution, Aircraft, Mach number, Aircraft carrier, Aircraft noise, Flight deck


Major developments over the past decade in aeroacoustic beamforming techniques provide more accurate estimates of jet noise source phenomena. In a recent experiment, near and mid-field measurements of an F-22A using linear and planar microphone arrays were taken at various engine conditions about the jet plume. To locate and provide accurate amplitude levels of jet noise sources, conventional beamforming techniques are used with various array shading methods. Equivalent source reconstructions are shown for different engine conditions, observation angles, and frequencies to explore the source region. In addition, different datasets from spatially separated arrays are combined for improved source reconstructions and to account for spatially dependent spectral content. These results are preliminary to further techniques-such as deconvolution methods-to better understand noise source mechanisms within the jet plume. [Work supported by ONR.].

Concepts: Sound, Array, Source, Start, Turbofan, Jet aircraft, Begin, Aircraft noise


In this paper, the development and use of acoustic energy harvesting technology as a source of local power for aeroacoustic sensing and control applications is discussed. As an example, the application of acoustic energy harvesting as a primary local power source for aircraft engine noise reduction technology is addressed. Noise generated in turbofan engine nacelles can easily exceed 150 dBSPL, presenting a primary motivation for aircraft noise reduction technologies. Adaptive noise control approaches require less power than active methods and can outperform passive techniques (e.g., by actively tuning an otherwise passive system to a changing noise spectrum). Locally sourced power is highly desirable in this application to eliminate cabling in a difficult to access, harsh environment. The low power requirements can be reasonably supplied with harvested acoustic energy, particularly given the large acoustic intensities in and around aircraft engine nacelles. The detailed development approach and experimental results of acoustic energy harvesting using an electromechanical Helmholtz resonator will be presented. Additionally, alternative Helmholtz resonator variants and other aeroacoustic applications of acoustic energy harvesting will be reviewed.

Concepts: Acoustics, Sound, Noise pollution, Power, Fighter aircraft, Turbofan, Aircraft noise, Aircraft engine