Download or read book Estimate of Aircraft Flyover Noise Reduction by Application of Active Noise Control to Engine Fan Tones written by R. E. Kraft and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development and Demonstration of Active Noise Control Concepts written by and published by . This book was released on 2000 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Active Control of Fan Noise written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-28 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: An extension of a prior study has been completed to examine the potential reduction of aircraft flyover noise by the method of active noise control (ANC). It is assumed that the ANC system will be designed such that it cancels discrete tones radiating from the engine fan inlet or fan exhaust duct, at least to the extent that they no longer protrude above the surrounding broadband noise levels. Thus, without considering the engineering details of the ANC system design, tone levels am arbitrarily removed from the engine component noise spectrum and the flyover noise EPNL levels are compared with and without the presence of tones. The study was conducted for a range of engine cycles, corresponding to fan pressure ratios of 1.3, 1.45, 1.6, and 1.75. This report is an extension of an effort reported previously. The major conclusions drawn from the prior study, which was restricted to fan pressure ratios of 1.45 and 1.75, are that, for a fan pressure ratio of 1.75, ANC of tones gives about the same suppression as acoustic treatment without ANC. For a fan pressure ratio of 1.45, ANC appears to offer less effectiveness from passive treatment. In the present study, the other two fan pressure ratios are included in a more detailed examination of the benefits of the ANC suppression levels. The key results of this extended study are the following observations: (1) The maximum overall benefit obtained from suppression of BPF alone was 2.5 EPNdB at high fan speeds. The suppression benefit increases with increase in fan pressure ratio (FPR), (2) The maximum overall benefit obtained from suppression of the first three harmonics was 3 EPNdB at high speeds. Suppression benefit increases with increase in FPR, (3) At low FPR, only about 1.0 EPNdB maximum reduction was obtained. Suppression is primarily from reduction of BPF at high FPR values and from the combination of tones at low FPR, (4) The benefit from ANC is about the same as the benefit from passive treatment at fan pressure ra...

Download or read book Active Control of Fan Noise Feasibility Study written by and published by . This book was released on 1996 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Federal Aircraft Noise Abatement Plan written by United States. Office of Noise Abatement and published by . This book was released on 1969 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 35th Aerospace Sciences Meeting Exhibit written by and published by . This book was released on 1997 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fan Noise Reduction An Overview written by Edmane Envia and published by . This book was released on 2001 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Potential Subjective Effectiveness of Active Interior Noise Control in Propeller Airplanes written by Clemans A. Powell and published by . This book was released on 2000 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Active noise control technology offers the potential for weight-efficient interior noise reduction, particularly for propeller aircraft. However, there is little information on how passengers respond to this type of interior noise control. This paper presents results of two experiments that use sound quality engineering practices to determine the subjective effectiveness of hypothetical active noise control (ANC) systems in a range of propeller aircraft. The two experiments differed by the type of judgments made by the subjects: pair comparisons based on preference in the first and numerical category scaling of noisiness in the second. Although the results of the two experiments were in general agreement that the hypothetical active control measures improved the interior noise environments, the pair comparison method appears to be more sensitive to subtle changes in the characteristics of the sounds which are related to passenger preference. The reductions in subjective response due to the ANC conditions were predicted with reasonable accuracy by reductions in measured loudness level. Inclusion of corrections for the sound quality characteristics of tonality and fluctuation strength in multiple regression models improved the prediction of the ANC effects.

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Scientific and Technical Publications written by and published by . This book was released on 1987 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book JSME International Journal written by and published by . This book was released on 2006 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Federal Aircraft Noise Research Development and Demonstration Programs FY73 FY75 written by Interagency Aircraft Noise Research Panel and published by . This book was released on 1975 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Federal Aircraft Noise Abatement Plan written by and published by . This book was released on 1971 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aircraft Engine Noise Reduction written by and published by . This book was released on 1972 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Assessment of Propeller Aircraft Noise Reduction Technology written by and published by . This book was released on 1995 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Estimation of Cumulative Noise Reduction at Certification Points for Supersonic Civil Aeroplane Using the Programmed Thrust Management at Take off and Approach written by Artur Mirzoyan and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reduction of the cumulative noise level at certification points applying to the supersonic civil aeroplane is estimated in the paper. The reduction is obtained by using an programmed thrust management with Programmed Lapse Rate based on the variation of engine power setting at take-off and approach. The use of proposed programmed reduced noise thrust management requires a change of the conventional noise certification procedures as well as further implementation as fully automated system (Variable Noise Reduction System) into aircraft/engine control system. The main engine noise sources such as the fan and exhaust jet are taken into account in the estimation. It is shown that the cumulative noise level using proposed programmed thrust management is lower by 10.7,Äì12.2 EPNdB than using the conventional engine thrust control as currently applied to subsonic jet aeroplanes at take-off and approach.