• The Journal of the Acoustical Society of Korea
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• v.15 no.4
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• pp.12-17
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• 1996

With the increase in discomfort of living by serious traffic noise pollution, the desire of relieving from discomfort is boosted up more than ever. For this reason, the researches on environmental impact assessmient and noise pollution control are highly required. This research was aimed to analyze the physical characteristics of noise caused by high-speed train in foreign countries by literature survey and field data. And with the attained results, the exterior noise level around Chon-An station, the first station planned for the high-speed train in this country, was estimated. The results of this study might be used as a tool for predicting the unavoidable noise, lessening the noise impact caused by the high-speed train, and preparing the noise prevention measures for the interior space and the exterior around stations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.480-483
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• 2007

Recently, many apartment houses were built in nearby road and railway. Road traffic noise level and railroad traffic noise level are important factors on apartment houses inhabitant's acoustic comforts. The measurement methods which noted by Ministry of Construction & Transportation, Ministry of Environment and Korean Industrial Standard are used for measurement of exterior noise at apartment houses. The purpose of this study compare the noise level characteristic by the measuring methods and evaluating methods. The results show that road traffic noise in the daytime appeared by not greatly noise level difference by the measuring method and evaluating methods. But railroad traffic noise appeared by greatly the noise level difference by the equivalent noise level(1hour) and continuous time.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.123-125
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• 2010

As the exterior noise emitted by a vehicle is getting more and more attention, simulated pass-by measurements become more important. This well established method provides information about the total noise emitted by the vehicle. For a vehicle manufacturer it is not only interesting to know about the total noise but also to know how this total exterior noise is composed of different contributions, such as for example the contribution of the engine, the intake or exhaust system. Transfer path analysis (TPA) provides a separation of these contributions for each of the pass-by microphones alongside the track. Presented is a method for fast and efficient determination of the contributions of multiple sources using operational transfer path analysis (OTPA). The calculation of the transfer characteristics between the reference measurement points on the vehicle and the corresponding response points of both microphone lines are carried out while operation of the vehicle. As result of the contribution analysis from operational transfer path analysis, the characteristic noise level as function of the covered distance is displayed for all individual sound sources, thus providing in depth information for sound quality engineering.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.569-569
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• 2014

The interior vehicle noise due to the exterior aerodynamic field is an important topic in the acoustic design of a car. The air flow detached from the A-pillar and impacting the side windows are of particular interest as they are located close to the driver / passenger and provides a lower insulation index than the trimmed car body parts. This paper presents a numerical analysis method for a simplified vehicle model. The internal air cavity including trim component are included in the simulation. The car body includes the windshield and two side windows. The body is made of aluminum and trimmed with porous layers. The methodology proposed in this paper relies on two steps: the first step involves the computation of the exterior flow and turbulence induced non-linear acoustic field using CFD Code. The second step consists in the computation of the vibro-acoustic transmission through the window using the finite element vibro-acoustic solver Actran.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.209-214
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• 2009

In this research, an external noise distribution of a HST has been analyzed by using a ray tracing techniques. An aero-dynamic noise generated from a bogie has been considered as a major noise source. Then a distribution of the noise on the outside of the vehicle is calculated using a ray noise technique. The models simulated are two different acoustic fields: an open field and a tunnel. In order to evaluate the noise effects, an exterior structure has been modified by using a different length of skirts. Various application schemes of reducing an environmental noise level will be expected for a HST based on this research.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.306-311
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• 2002

Non-singular boundary element method (BEM) codes are developed in acoustics application. The BEM code is then used to calculate unknown boundary surface normal displacements and surface pressures from known exterior near Held pressures. And then the calculated surface normal displacements and surface pressures are again applied to the BEM in forward in order to calculate reconstructed field pressures. The initial exterior near field pressures are very well agreed with the later reconstructed field pressures. Only the same number of boundary surface nodes (1178) are used far the initial exterior pressures which are initially calculated by Finite Element Method (FEM) and BEM. Pseudo-inverse technique is used for the calculation of the unknown boundary surface normal displacements. The structural object is a tuning fork with 128.4 Hz resonant. The boundary element is a quadratic hexahedral element (eight nodes per element).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.296-297
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• 2012

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.489-493
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• 2007

Mmulti-domain noise analysis method using Power Flow Boundary Element Method(PFBEM) has been developed successfully. Some applications are introduced. several examples. PFBEM is a numerical analysis method formulated by applying Boundary Element Method(BEM) to Power Flow Analysis(PFA). PFBEM is very powerful in predicting noise level in medium-to-high frequency ranges. However there are restrictions in analyzing the coupled structures and multi-media. In this paper, an analysis method for multi-domain acoustic problems in the diverse acoustic fields is suggested. And the developed method is applied to the car interior and exterior multi-domain noise analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.356-357
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• 2012

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.283-285
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• 2013