Sound propagation over uneven ground and irregular topography semiannual status report no. 6

Cover of: Sound propagation over uneven ground and irregular topography |

Published by School of Mechanical Engineering, Georgia Institute of Technology in Atlanta, Ga .

Written in English

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Subjects:

  • Acoustic surface waves.,
  • Sound.

Edition Notes

Book details

Statementby Yves H. Berthelot ... [et al.].
SeriesNASA-CR -- 182352., NASA contractor report -- NASA CR-182352.
ContributionsBerthelot, Yves Henri., United States. National Aeronautics and Space Administration.
The Physical Object
FormatMicroform
Pagination1 v.
ID Numbers
Open LibraryOL15285267M

Download Sound propagation over uneven ground and irregular topography

Niques for predicting the effects of irregular topography on long range sound propagation in the atmosphere. Irregulax topography here is understood to imply a ground surface. Theoretical, computational, and experimental techniques were developed for predicting the effects of irregular topography on long range sound propagation in the atmosphere.

Irregular topography is understood to imply a ground surface that: (1) is not idealizable as being perfectly flat, or (2) that is not idealizable as having a constant specific acoustic : Yves H. Berthelot, Allan D. Pierce, James A. Kearns, Ji-Xun Zhou. The development of theoretical, computational, and experimental techniques for predicting the effects of irregular topography on long range sound propagation in the atmosphere is discussed.

Irregular topography here is understood to imply Sound propagation over uneven ground and irregular topography book ground surface that (1) is not idealizable as being perfectly flat or (2) that is not idealizable as having a Author: A.

Pierce, G. Main, J. Kearns, D. Benator, J. Parish. l [[[[[. i i i i i i i i nag-i semiannual report, page 1 semiannual status report nasa grant nag-i sound propagation over uneven ground and irregular topography. Get this from a library. Sound propagation over uneven ground and irregular topography: semiannual status report no.

[Yves Henri Berthelot; United States. National Aeronautics and Space Administration.;]. Theoretical, computational, and experimental techniques for predicting the effects of irregular topography on long range sound propagation in the atmosphere was developed.

Irregular topography here is understood to imply a ground surface that is not idealized as being perfectly flat or that is not idealized as having a constant specific acoustic : A. Pierce, G. Main, J. Kearns, D. Benator, J. Parish. Sound propagation over uneven ground and irregular topography.

By A. Pierce, Jr. Parish, D. Benator, J. Kearns and G. Main. Abstract. The development of theoretical, computational, and experimental techniques for predicting the effects of irregular topography on long range sound propagation in the atmosphere is discussed.

The goal of this research is to develop theoretical, computational, and experimental techniques for predicting the effects of irregular topography on long range sound propagation in the atmosphere. Irregular topography here is understood to imply a ground surface that is not idealizable as being perfectly flat or that is not idealizable as having a constant specific.

Sound propagation over uneven ground and irregular topography: Authors: Berthelot, Yves H.; Impedance, Mathematical Models, Sound Waves, Topography, Wave Propagation, Algorithms, Fourier Transformation, Sound Pressure, Surface Roughness: The sound pressure level can be regarded as a function of frequency, sound speed in air, heights of.

Sound propagation over uneven ground and irregular topography: Authors: Berthelot, Yves H and experimental techniques for predicting the effects of irregular topography on long range sound propagation in the atmosphere. Irregular topography is understood to imply a ground surface that is not idealizable as being perfectly flat or that is no.

For outdoor sound propagation over a locally reacting ground surface, the computed GF‐PE field is the sum of three terms: a direct wave, a specularly reflected wave, and a surface wave. Sound propagation over uneven ground and irregular topography.

By James A. Kearns, and experimental techniques were developed for predicting the effects of irregular topography on long range sound propagation in the atmosphere. Irregular topography is understood to imply a ground surface that: (1) is not idealizable as being perfectly flat.

Get this from a library. Sound propagation over uneven ground and irregular topography: semiannual status report. [Allan D Pierce; Langley Research Center.;].

Sound propagation over an irregular terrain with complex meteorological effects using the parabolic equation model F. Aballéa, J. Defrance Centre Scientifique et Technique du bâtiment (CSTB), 24, rue Joseph Fourier, F Saint-Martin-d’Hères, France Email: [email protected][email protected] Sound propagation over uneven ground and irregular topography.

By A. Pierce, G. Main and J. Kearns. Abstract. Theoretical, computational, and experimental techniques for predicting the effects of irregular topography on long range sound propagation in the atmosphere was developed.

Irregular topography here is understood to imply a Author: A. Pierce, G. Main and J. Kearns. LF Ground-Wave Propagation Over Irregular Terrain Article (PDF Available) in IEEE Transactions on Antennas and Propagation 59(4) - May with Reads How we measure 'reads'.

Get this from a library. Sound propagation over uneven ground and irregular topography: semiannual status report no. [James A Kearns; Allan D Pierce; Geoffrey L Main; Langley Research Center.]. SOUND PROPAGATION OVER UNEVEN GROUND AND IRREGULAR TOPOGRAPHY Semiannual R,eport, August - January Yves H.

Berthelot (Co-PI), Allan D. Pierce (Co-PI), Geoffrey L. Main (Co-PI), Ji-xun Zhou, and James A. Kearns School of Mechanical Engineering Georgia Institute of Technology Atlanta, Georgia Submitted to. SOUND PROPAGATION OVER UNEVEN GROUND AND IRREGULAR TOPOGRAPHY Semiannual Report, February - August by James A.

Kearns, AIL, n D. Pierce, and Geoffrey L. Main School of Mechanical Engineering Georgia InstituteofTechnology Atlanta, Georgia Submitted to National Aeronautics and Space Administration Langley Research Center.

Sound impact of road and railway infrastructures are more and more severely regulated by European laws: acceptable thresholds in emission and reception are decreasing. This implies to develop propagation models able to take many phenomena into account at the same time (meteorology, uneven ground, impedances discontinuities).

The parabolic equation (PE) is Cited by: 6. Sound propagation over uneven ground and irregular topography [microform]: semiannual status report no. Sound propagation over uneven ground and irregular topography [microform]: semiannual status report / b Bank management and portfolio behavior / Donald D.

Hester, James L. Pierce; The philosophy of Aristotle [by] D. Allan. Atmospheric sound propagation over large-scale irregular terrain Martin Almquist 1, Ilkka Karasalo y2 and Ken Mattsson z1 1 Department of Information ecThnology, Uppsala University 2 Department of Hydroacoustics, Swedish Defence Research Agency, SE Stockholm, Sweden Septem Abstract A benchmark problem on atmospheric sound propagation over ir.

SOUND PROPAGATION OVER UNEVEN GROUND AND IRREGULAR TOPOGRAPHY Semiannual Report, August - February by Yves H. Berthelot, James A. Kearns, Allan D. Pierce, and Geoffrey L. Main School of Mechanical Engineering Georgia Institute of Technology Atlanta, Georgia Submitted to National Aeronaiitics and Space A generalized polar coordinate method for sound propagation over large-scale irregular terrain Article in The Journal of the Acoustical Society of America (5).

SOUND PROPAGATION OVER UNEVEN GROUND AND ffiREGULAR TOPOGRAPHY Semiannual Report, January -July by Yves H. Berthelot (Co-PI), Allan D. Pierce (Co-PI) James A. Kearns, and Ji-Xun Zhou School of Mechanical Engineering Georgia Institute of Technology Atlanta, Georgia Submitted to National Aeronautics and Space Administration.

Journal of Sound and Vibration () 98(l), ON THE LONG RANGE PROPAGATION OF SOUND OVER IRREGULAR TERRAIN M. HOWE i Bolt Beranek and Newman Inc, 50 Moulton Street, Cambridge, MassachusettsUS.A. (Received 14 Januaryand in revised form 15 March The theory of sound propagation over randomly irregular, nominally plane Cited by:   A benchmark problem on atmospheric sound propagation over irregular terrain has been solved using a stable fourth-order accurate finite difference approximation of a high-fidelity acoustic model.

A comparison with the parabolic equation method and Cited by: 9. Sound Propagation Over Uneven Ground and Irregular Topography- National Aeronautics and Space Administration, Langley Research Center Hampton, VirginiaSemiannual Report, February July ; Yves H.

Berthelot, (Co-PI), Allan D. Pierce (Co-PI), Ji-Xun Zhou, Geoffrey L. Main (Co-PI), Pei-Thi Chen, James A. Kearns, and Nathaniel Chisholm.

/flflqL y GmJ- CR, yZC65 / SEMIANNUAL STATUS REPORT No. 5 NASA GRANT NAG SOUND PROPAGATION OVER UNEVEN GROUND AND IRREGULAR TOPOGRAPHY Semiannual Report, February - July by Yves H. Berthelot (Co-PI), Allan D.

Pierce (Co-PI), Ji-xun Zhou, Geoffrey L. Main (Co-PI), Pei-Thi Chen, James A. Kearns, and Nathaniel. CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): Abstract [] Sound impact of road and railway infrastructures are more and more severely regulated by European laws: acceptable thresholds in emission and reception are decreasing.

This implies to develop propagation models able to take many phenomena into account at the same time (meteorology, uneven ground.

Sound propagation over irregular terrain with complex meteorological effects using the parabolic equation model. By François-Edern Aballéa and Jérome Defrance. uneven ground, impedances discontinuities). The parabolic equation (PE) is one of those numerical methods. Its main purpose is to predict long-range sound propagation under Author: François-Edern Aballéa and Jérome Defrance.

FDTD simulations of low-frequency sound would be feasible even over large ranges, but propagating low-frequency sound behaves differently than high-frequency sound. Differences are particularly expected in the case of reflection and diffraction.

Reflection at finite impedance ground is strongly dependent on frequency (e.g., Chessell 3 3. by: 8. Atmospheric Sound Propagation Over Large-Scale Irregular Terrain Abstract A benchmark problem on atmospheric sound propagation over irregular terrain has been solved using a stable fourth-order accurate finite difference approximation of a high-fidelity acoustic model.

A comparison with the topography and the type of ground. The 33 rd International Congress and Exposition on Noise Control Engineering Sound propagation over an irregular terrain with complex meteorological effects using the parabolic equation model (meteorology, uneven ground, impedances discontinuities).

The parabolic equation (PE) is one of those numerical methods. Its main purpose is to Author: F. Aballéa and J. Defrance. ATMOS can predict noise propagation for a given weather condition.

The computer code takes into account the nature of the ground, the geometry of the barriers and its acoustic properties. Simulation results are used to quantify the combined effects of topography and weather conditions on sound propagation.

There is an extensive body of theory, and some laboratory measurements, of sound propagation over a surface of finite impedance. There are also reliable measurements of outdoor sound propagation in near‐horizontal directions over the ground. In an attempt to relate these more closely, we have made carefully controlled measurements at ranges from 1 to ft, in most cases over Cited by:   This paper deals with the exact solution of surface gravity waves in an ocean with irregular bed topography.

In order to obtain water surface elevation and run-up of infra-gravity waves when the bed is either wavy or exponential, closed form solutions are obtained.

Numerical computations indicate that when solitary wave or sinusoidal wave conditions are applied at the Cited by: 2. The polar coordinate method in You [Ph.D. thesis, The University of Mississippi ()] is rederived in differential form and is generalized by defining a local, continuously varying, radius of curvature.

The generalization makes it possible to compute sound propagation over arbitrary large-scale terrain where the local radii of curvature are much larger than an acoustic Cited by: 7. Effects of irregular topography on ground motion for incident P, SV and the propagation of Rayleigh waves are studied by combining finite element method with modified transmitting boundary.

Theoretical models include isolated protruding topography and similar adjacent protruding topography.

The conclusion drawn from this study is that the effects of isolated protruding topography Cited by: 1. Analysis of scattered waves on ground with irregular topography using the direct boundary element method and on ground with irregular topography and that without irregularities. However, they do not clarify induced by irregular ground surfaces in terms of the scattered-wave contribution in a time domain.

James A Kearns has written: 'Sound propagation over uneven ground and irregular topography' Asked in Energy Transfer of heat energy around the Earth from uneven. A new boundary-element method for predicting outdoor sound propagation over uneven ground is presented.

This allows the sound field around complex boundaries (various absorptive properties and shapes) and in the presence of refraction to be calculated accurately.

The total sound pressure is expressed as the sum of the incident pressure and the pressure Cited by: The simplest case of sound propagation is that of a point source emitting spherical waves in an isotropic and homogeneous atmosphere over flat uniform ground; see Fig.

such conditions the sound pressure at the receiver’s position can be calculated using Chien and Soroka’s formulation derived from Weyl-Van der Pol’s theory, (1) p = 1 R 1 e i kR 1 + Q 1 R 2 Cited by: 8.

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