Sound Propagation
Mostrando 1-12 de 28 artigos, teses e dissertações.
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1. Molecular dynamic study of the jet noise about the micro-scale tube
This paper studies the two-dimensional micro-scale molecular simulations of the jet flow using Lagrange discrete systems and adopting Andresen flexible constraint mechanism. At the effects of different excitation conditions and boundary conditions, the low Mach number flow field and sound field are obtained, and characteristic results are given. At the jet f
Matéria (Rio J.). Publicado em: 2014-12
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2. A study on acoustic behavior of poroelastic media bonded between laminated composite panels
A study on the acoustic behavior of double-walled panels, with sandwiched layer of porous materials is presented within Classical Laminated Plate Theory (CLPT) for laminated composite panels. For this purpose, equations of wave propagation are firstly extracted based on Biot's theory for porous materials, then the transmission loss (TL) of the structure is e
Lat. Am. j. solids struct.. Publicado em: 2014
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3. Simulação da propagação de ondas ultrassônicas longitudinais em materiais estruturais aeroespaciais / Simulating the propagation of longitudinal ultrasonic waves in aerospace structural materials
The use of composite materials in the aerospace industry is increasing due to its low ratio between density and mechanical strength. To perform non-destructive testing using ultrasound, it is necessary to know the sound velocity in these materials. It is not always possible to manufacture physical prototypes during the development of a project because of tim
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 10/08/2012
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4. Proposta metodológica para elaboração de mapas de ruído em ambiente SIG, segundo norma ISO 9613-2
Noise mapping is a new activity with growing awareness among public officials and communities. This work presents a methodological proposal for the generation of noise maps in a Geographic Information System (GIS), based on ISO 9613-2, which standards the calculus for noise attenuation during propagation outdoors. Besides the definitions of methodological pr
Publicado em: 2011
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5. Does the golden lion tamarin, Leontopithecus rosalia (Primates: Callitrichidae), select a location whithin the forest strata for long distance communication?
The effectiveness of auditory signals for long distance communication depends on environmental, biological and behavioral factors. Because the environment is not homogenous, it is expected that vocalizing animals would emit signals from locations (perches) that would facilitate call propagation and perception. Perching behavior has been widely documented in
Zoologia (Curitiba). Publicado em: 2010-04
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6. Aeroacoustics of dual-stream jets with application to turbofan engines.
A Computational Aeroacoustics (CAA) and a novel semi-empirical model is developed for predicting the noise generated by the jet flow through dual stream (coaxial) nozzles, as found in modern turbofan engines. The acoustic source model was developed in a 2D and 3D framework, based on the Lilley s Equations, following the traditional MGBK method from NASA Lang
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 26/06/2009
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7. Materiais e técnicas contemporâneas para controle de ruído aéreo em edifícios de escritórios: subsídios para especificações / Contemporaneous materials and techniques to air noise control on corporate edifices: specification foundations
Big cities have been taken the ground thought freeways and avenues, where constant and loud noise takes place. At theses ways, corporate edifices are also often established, so they naturally become exposed to the external noise interference, regardless the own internal facilities noising. The consequence is that people how work at these places are more pron
Publicado em: 2009
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8. Modelagem Computacional da Propagação Acústica Proveniente de Fontes Multifrequênciais Usando Guias Digitais de Ondas / Computational Modeling of Wave Propagation from Multifrequêncial Source Using Mesh Digital Waveguide
The goal of this research is the creation of virtual acoustic environments, in this context, was constructed a computational tool, aiming to the acoustic modeling of reverberation environment. In this way, it was necessary to elaborate a numerical system able to simulate the wave sound propagation and, mainly its interactions with the surfaces encountered in
Publicado em: 2009
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9. Aeroacoustics of dual-stream jets with application to turbofan engines.
A Computational Aeroacoustics (CAA) and a novel semi-empirical model is developed for predicting the noise generated by the jet flow through dual stream (coaxial) nozzles, as found in modern turbofan engines. The acoustic source model was developed in a 2D and 3D framework, based on the Lilley s Equations, following the traditional MGBK method from NASA Lang
Publicado em: 2009
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10. Use of Component Mode Synthesis and Axial Splits in Ducts for Noise Control of Higher Order Duct Mode / Utilização de síntese modal de componentes e particionamento axial de dutos para controle dos modos acústicos de alta ordem
In this study, the proposal of this work is centered in the noise reduction in ducts that became, over the years, a field of intense application. The traditional approach to acoustic noise control in ducts uses passive techniques and fixed reactive silencers to mitigate the noise. In this moment, the Active Control of Noise (ANC) is an attractive approach to
Publicado em: 2009
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11. Caracterização acustica de ginasios de esportes multifuncionais da cidade de Campinas, SP / Characterization acoustics multipurpose gymnasium of sports of the Campinas s city
Similar sonorous stimulus may promote different sound perceptions in the environment. Sonorous stimulus may be objectively evaluated by acoustic measurements however, sound perceptions evaluation (subjectively) requires another specific methods. Spaces like sport gymnasiums can promote different sensations for the users depending on their activities. This ty
Publicado em: 2008
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12. Retroanálise probabilista aplicada à análise dinâmica da cravação de estacas. / Probabilistic back-analysis applied to dynamic loading test for pile driving.
An dynamic loading test can be performed in concrete piles, bored piles, drilled shafts, auger cast-in-place (continuous flight auger) piles. Such essay bases on the Theory of the Propagation of Wave in piles with the aim of evaluate the capacity of static load mobilized from the dynamic event. The analysis of the test is made by a PC program (p.e. CAPWAP or
Publicado em: 2008