منابع مشابه
Understanding jet noise.
Jets are one of the most fascinating topics in fluid mechanics. For aeronautics, turbulent jet-noise modelling is particularly challenging, not only because of the poor understanding of high Reynolds number turbulence, but also because of the extremely low acoustic efficiency of high-speed jets. Turbulent jet-noise models starting from the classical Lighthill acoustic analogy to state-of-the ar...
متن کاملEffects of jet engine noise and performance feedback on perceived workload in a monitoring task.
This study examined the effects of exposure to intermittent jet aircraft noise (70 dBA or 95 dBA maximum intensity) and knowledge of results concerning signal detections (hit-KR) on performance efficiency and perceived workload in a 40-min visual vigilance task. The noise featured a Doppler-like quality in which planes seemed to approach from the monitor's left and recede to the right. Perceptu...
متن کاملThe influence of jet engine noise on hearing of technical staff.
BACKGROUND Due to high sound pressure levels (SPLs), noise produced by jet planes may be harmful to hearing of people working in their proximity. The aim of this study was to assess the effects of exposure to jet engine noise on technical staff hearing. MATERIAL AND METHODS The study comprised 60 men, aged 24-50 years, employed in army as technical staff and exposed to jet engine noise for 6-...
متن کاملNovelty detection in jet engine vibration spectra
This paper presents a principled method for detecting “abnormal” content in vibration spectra obtained from rotating machinery. We illustrate the use of the method in detecting abnormality in jet engine vibration spectra corresponding to unforeseen engine events. We take a novelty detection approach, in which a model of normality is constructed from the typically large numbers of examples of “n...
متن کاملEstimator design in jet engine applications
Jet engines are nonlinear dynamical systems for which an exact mathematical model cannot be used for estimator design, because it is either not available or so complex that it does not fit the necessary assumptions. Thus, classical analytical tools for studying standard system properties like observability, which is very important in estimator design, cannot be directly applied. Generally, for ...
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ژورنال
عنوان ژورنال: Journal of the Japan Society for Aeronautical and Space Sciences
سال: 1973
ISSN: 0021-4663
DOI: 10.2322/jjsass1969.21.164