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dc.contributor.authorPera, Nicholas Matthewen_US
dc.date.accessioned2017-06-14T08:00:45Z
dc.date.available2017-06-14T08:00:45Z
dc.date.issued2017-06-13en_US
dc.identifier.othervt_gsexam:10173en_US
dc.identifier.urihttp://hdl.handle.net/10919/78188
dc.description.abstractRotorcraft flyover noise has long been a field of study for researchers. This is because for many people, the sounds produced by these vehicles are found to be extremely annoying. The focus of this thesis is to recreate the time-varying rotorcraft noise at the source for a single emission angle. Then, through interpolation between emission angles, produce a simulated flyover at the source that can then be propagated to a receiver. This will allow for the creation of a simulated flyover without the need of having to use a physical aircraft, or pre-existing data from some type of data collection means, such as a microphone array. The current methods are limited to a predefined length of data in order to synthesize signals. It has been documented that synthesizing flyover noise, from direct use of physical flyover recordings through an empirical approach, yields a high fidelity signal, as long as both unmodulated and modulated components are present. In order to extend these signals indefinitely, models for the amplitude and phase modulation must be developed. A band-limited random process will be explored for both the amplitude and phase modulations. An overlap-add technique, as well as a randomization technique and a modified phase modulation signal, defined as the "residual", will also be attempted in order to model the phase modulation. The results from this work have successfully found a means in which to produce a viable model of the amplitude modulation. Further investigation is still required in order to produce a model of the phase modulation which results in a high-fidelity model that can be extended indefinitely.en_US
dc.format.mediumETDen_US
dc.publisherVirginia Techen_US
dc.rightsThis item is protected by copyright and/or related rights. Some uses of this item may be deemed fair and permitted by law even without permission from the rights holder(s), or the rights holder(s) may have licensed the work for use under certain conditions. For other uses you need to obtain permission from the rights holder(s).en_US
dc.subjectrotorcraften_US
dc.subjectsynthesisen_US
dc.subjectpropagationen_US
dc.subjectflyover noiseen_US
dc.titleDevelopment of a Method for Analysis and Incorporation of Rotorcraft Fluctuation in Synthesized Flyover Noiseen_US
dc.typeThesisen_US
dc.contributor.departmentAerospace and Ocean Engineeringen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineAerospace Engineeringen_US
dc.contributor.committeechairFuller, Christopher R.en_US
dc.contributor.committeechairLowe, Kevin T.en_US
dc.contributor.committeememberPhilen, Michael Keithen_US
dc.contributor.committeememberRizzi, Stephen A.en_US


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