<i>Acoustics: An Introduction to Its Physical Principles and</i> <i>Applications. 1989 Edition</i>

Pierce, Allan D.; Beyer, Robert T.

doi:10.1121/1.399390

Cited by 131 publications

(161 citation statements)

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“…Ekuazio mota hori anplitude mugatuko uhinen zabaltzea imitatzeko erabili ohi da. Hainbat egilek lortutako orokortzeetan ingurune barreiatzaileetan gertatzen diren beste zenbait efektu izan dituzte kontuan: zabalpen geometrikoa [9], ingurune heterogeneoak [10,11], lasaikun tzaprozesuak [12]... (1) ABE ekuazioak fenomeno horiek guztiak kontuan hartzen ditu soinu-eztandaren hedapena modelatzeko.…”

Section: Burgersen Ekuazioaren Soluzioaunclassified

Zenbakizko biskositateak eragindako soinu-eztandaren simulazioaren zailtasunak

Pozo¹

2018

EKAIA

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Laburpena:Hegazkin supersonikoek eragindako soinu-eztandaren hedapena eremu hurbiletik lurreraino zehatz-mehatz simulatzea ez da erraza. Ereduaren denbora-tarte handietarako propietateak babesten dituzten zenbakizko metodoak behar dira. Artikulu honetan, soinu-eztandaren minimizazioarekin erlazionaturik dagoen optimizazio eta alderantzizko diseinu-problema ikertu dugu. Bereziki, bere soluzioaren hurbilketen eraginkortasuna mantentzeko gakoak ematen ditugu.Hitz gakoak: Soinu-eztanda, denbora-tarte handiko portaera, biskositatea, zenbakizko metodoak. Abstract:Simulating the propagation of the sonic-boom precisely from the near-field of a supersonic airplane down to the ground level is not easy. It requires numerical schemes that preserve the large-time properties of the model. In this article we deal with an optimization and inverse design problem related to the sonic-boom minimization. In particular, we emphasize the key points that need to be handled in order to keep the efficiency of the approximations of its solution.

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Section: Burgersen Ekuazioaren Soluzioaunclassified

Zenbakizko biskositateak eragindako soinu-eztandaren simulazioaren zailtasunak

Pozo¹

2018

EKAIA

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“…If all of m, χ, Q vanish, Pierce [7] has shown that, when the viscosities and conductivity are small parameters, the compressing process can be further decomposed into an acoustic mode, which is characterized by pressure and effectively isentropic, and an entropy mode, which is characterized by entropy and effectively isobaric. We shall adopt this concept for our mode splitting.…”

Section: Modes Splitting Of the Compressing Processmentioning

confidence: 99%

“…Although analysis in spectral space can be simplified to algebraic equations and lead to various dispersion relations [7], the mathematical nature of the governing differential equations is no as clear as the operator analysis in physical space. If the high-order differential operator governing a multiprocess flow can be factorized, then the processes or modes in the flow are physically decoupled, and otherwise are coupled.…”

Section: Introductionmentioning

confidence: 99%

“…The root of such a situation may be traced in part to the rich but multiple-road development of aeroacoustics. The basic framework of this branch was settled by Rayleigh [2] for whom the HD was the main tool to identify the sound wave (For a detailed review of Rayleigh's theory in the context of aeroacoustics see Doak [3]), which has been followed by Lagerstrom et al [4], Wu [5], Chu and Kovasznay [6], and Pierce [7], among others, in their analytical studies on the linearized or iterative theory of fundamental processes and their splitting from late 1940s-1980s. But this line of development was overwhelmed by Lighthill's ingenious acoustic analogy theory [8] which puts the HD aside and represents the local mechanisms responsible for sound generation by a set of "equivalent quadrupole sources" in a fictitious and otherwise undisturbed medium where the sound speed is constant.…”

Section: Introductionmentioning

confidence: 99%

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On a general theory for compressing process and aeroacoustics: linear analysis

Mao

Shi

2010

Acta Mech Sin

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Of the three mutually coupled fundamental processes (shearing, compressing, and thermal) in a general fluid motion, only the general formulation for the compressing process and a subprocess of it, the subject of aeroacoustics, as well as their physical coupling with shearing and thermal processes, have so far not reached a consensus. This situation has caused difficulties for various in-depth complex multiprocess flow diagnosis, optimal configuration design, and flow/noise control. As the first step toward the desired formulation in fully nonlinear regime, this paper employs the operator factorization method to revisit the analytic linear theories of the fundamental processes and their decomposition, especially the further splitting of compressing process into acoustic and entropy modes, developed in 1940s-1980s. The flow treated here is small disturbances of a compressible, viscous, and heat-conducting polytropic gas in an unbounded domain with arbitrary source of mass, external body force, and heat addition. Previous results are thereby revised and extended to a complete and unified theory. The theory provides a necessary basis and valuable guidance for developing corresponding nonlinear theory by clarifying certain basic issues, such as the proper choice of characteristic variables of compressing process and the feature of their governing equations.

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“…To literally quote Pierce [4], reciprocity refers to the situation for which a magnitude associated with an ''effect'' at a point is unchanged when the location of ''cause'' and ''point of observation'' are interchanged. The current work shows that reciprocity does hold when the two transducers are identical.…”

Section: Introductionmentioning

confidence: 99%

Apparent transducer non-reciprocity in an ultrasonic flow meter

Deventer

Delsing

2002

Ultrasonics

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This paper investigates the effects of non-identical ultrasonic transducers on reciprocity and zero-flow calibration in transit time flow meters. According to the theorem of reciprocity, there should not be any difference between the up-and downstream acoustic times of flight in a zero-flow situation. This would thus eliminate zero-flow estimation drifts. The flow meter is modeled as a one dimensional system with equivalent electrical circuits and simulated with simulation program with integrated circuits emphasis. The work shows that variations between the two transducers cause false estimates of flow and indicate which parameters have the largest influence. It indicates that reciprocity holds only for identical transducers. Ó

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Acoustics: An Introduction to Its Physical Principles and Applications. 1989 Edition

Cited by 131 publications

References 0 publications

Zenbakizko biskositateak eragindako soinu-eztandaren simulazioaren zailtasunak

Zenbakizko biskositateak eragindako soinu-eztandaren simulazioaren zailtasunak

On a general theory for compressing process and aeroacoustics: linear analysis

Apparent transducer non-reciprocity in an ultrasonic flow meter

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