Simulation by using a curved ground scale model of outdoor sound propagation under the influence of a constant sound speed gradient

Almgren, Martin

doi:10.1016/0022-460x(87)90531-1

Cited by 11 publications

(3 citation statements)

References 8 publications

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“…For convenience, the 'curved ground-analogy' [14] has been adopted by inverse curving of the terrain rather than curving sound rays for assessment of meteorological refraction.…”

Section: The Noise Propagation Methodsmentioning

confidence: 99%

Harmonoise: Noise Predictions and the New European Harmonised Prediction Model

NOTA,

VAN LEEUWEN

2023

Autumn Conference Acoustics 2004

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“…For convenience, the 'curved ground-analogy' [14] has been adopted by inverse curving of the terrain rather than curving sound rays for assessment of meteorological refraction.…”

Section: The Noise Propagation Methodsmentioning

confidence: 99%

Harmonoise: Noise Predictions and the New European Harmonised Prediction Model

NOTA,

VAN LEEUWEN

2023

Autumn Conference Acoustics 2004

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“…As mentioned in the introduction, moderately downward refraction is assumed. At longer propagation distances, the effect of an atmospheric gradient resulting in downward refraction can be approximated by bending the ground surface upward which is comparable to lowering intermediate buildings [33]. Figure (9) shows the effect of different heights of intermediate buildings.…”

Section: A Intermentioning

confidence: 99%

Urban Background Noise Mapping: The General Model

Wang¹,

Botteldooren²,

Renterghem³

et al. 2014

Acta Acustica united with Acustica

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Surveys show that inhabitants of dwellings exposed to high noise levels benefit from having access to a quiet side. However, current practice in noise prediction often underestimates the noise levels at a shielded façade. Multiple reflections between façades in street canyons and inner yards are commonly neglected and façades are approximated as perfectly flat surfaces yielding only specular reflection. In addition, sources at distances much larger than normally taken into account in noise maps might still contribute significantly. Since one of the main reasons for this is computational burden, an efficient engineering model for the diffraction of the sound over the roof tops is proposed, which considers multiple reflections, variation in building height, canyon width, façade roughness and different roof shapes. The model is fitted on an extensive set of full-wave numerical calculations of canyon-to-canyon sound propagation with configurations matching the distribution of streets and building geometries in a typical historically grown European city. This model allows calculating the background noise in the shielded areas of a city, which could then efficiently be used to improve existing noise mapping calculations. The model was validated by comparison to long-term measurements at 9 building façades whereof 3 were at inner yards in the city of Ghent, Belgium. At shielded façades, a strong improvement in prediction accuracy is obtained.

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“…A model has been proposed by Zorumski 249 to predict the effect of low-altitude propagation of a noise source. In the FLIGHT program the wind and temperature effects have been modelled following Rasmussen 250 Almgren 251 and Pierce 252 , using a series of Hankel transforms of the acoustic pressure. The model has been extended to model long-distance propagation.…”

Section: Far-field Noise Propagationmentioning

confidence: 99%

Aircraft noise prediction

Smith¹

1989

Aircraft Noise

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This contribution addresses the state-of-the-art in the field of aircraft noise prediction, simulation and minimisation. The point of view taken in this context is that of comprehensive models that couple the various aircraft systems with the acoustic sources, the propagation and the flight trajectories. After an exhaustive review of the present predictive technologies in the relevant fields (airframe, propulsion, propagation, aircraft operations, trajectory optimisation), the paper addresses items for further research and development. Examples are shown for several airplanes, including the Airbus A319-100 (CFM engines), the Bombardier Dash8-Q400 (PW150 engines, Dowty R408 propellers) and the Boeing B737-800 (CFM engines). Predictions are done with the flight mechanics code FLIGHT. The transfer function between flight mechanics and the noise prediction is discussed in some details, along with the numerical procedures for validation and verification. Some code-to-code comparisons are shown. It is contended that the field of aircraft noise prediction has yet not reached a sufficient level of maturity. In particular, some parametric effects cannot be investigated, issues of accuracy are not currently addressed, and validation standards are still lacking.

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Simulation by using a curved ground scale model of outdoor sound propagation under the influence of a constant sound speed gradient

Cited by 11 publications

References 8 publications

Harmonoise: Noise Predictions and the New European Harmonised Prediction Model

Harmonoise: Noise Predictions and the New European Harmonised Prediction Model

Urban Background Noise Mapping: The General Model

Aircraft noise prediction

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