• Journal of the Society of Naval Architects of Korea
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• v.29 no.1
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• pp.123-134
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• 1992

The reduction of the airborne noise level is essential to the comfortability for mien and passengers in ships. In this paper, the acoustic characteristics on the multilayered acoustic panel with the Helmholtz resonator was described analytically and experimentally. The design software based on the Transfer Matrix Analysis(TMA) method for the acoustic enclosing panel was developed. According to the change of the design parameters of the panel, verious transmission losses were obtained using the developed software. As a result, it was verified that the acoustic characteristics of the composite panel was excellent in comparison with the conventional acoustic partitioning structures. This panel can be applicable to the acoustic enclosure system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.466-467
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• 2013

• Journal of KSNVE
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• v.11 no.1
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• pp.15-20
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• 2001

홴(fan)은 모터로부터 회전력을 전달받아 공기동력인 풍량과 정압을 발생시켜 발열부품의 냉각 및 환기용으로 산업현장과 가전기기에서 널리 사용되고 있다. 과거 산업현장에서 주로 사용되어지던 송풍기가 가전기기에 적용되면서 홴에 대한 관심이 더욱 증폭되었는데 특히 국내에서 독자적인 소형 홴 연구가 본격적으로 시작된 것도 이 때이다. 가전에서의 홴은 고효율 뿐 만 아니라 주로 저소음화에 대한 연구에 초점이 맞추어져 있는데 이는 기존의 산업현장의 송풍기가 주로 풍량과 정압에 목표를 두고 개발해 왔던 것도 한 이유지만 구조적인 안정성 때문에 소음을 고려한 설계가 한계가 있었기 때문으로 저소음홴에 대한 응용기술이 충분히 발달하지 못했기 때문에 송풍기 기술을 그대로 받아들인 초창기 가전용홴은 소음이 높았다. 또한 가전기기는 모든 연령층이 사용하기 때문에 소음이 큰 제품은 항상 소비자 클레임의 원인이 되기 때문이다.(중략)

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.205-208
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• 2006

This paper proposes a new computational aeroacoustics method for an axial fan analysis. The major aeroacoustic noise source of an outdoor air-conditioner is the axial fan. It was revealed that the dominant noise source is the aerodynamic interactions between the rotating blade and stationary orifice. Many researches were focused on the fan only case. However, it does not fit to a real outdoor unit of air-conditioner. Especially, the inlet part of the axial fan of real system case is complex and not uniform. So, in order to identify the dominant noise source of axial fan, full outdoor unit analysis is important. Transient CFD analysis of full system was performed by commercial CFD code - SC/Tetra. Dominant noise source of the system was calculated by commercial CFN code - FlowNoise. The results show that not only BPF peaks but also broadband noise are similar to the measured data.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.945-948
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• 2004

A free vibration analysis of air-operated valve(AOV) is investigated. The vibration characteristics of AOV with size variations are studied. The effects of inner pressure on the natural frequencies are also studied. The analytical results are compared with expermental results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.8
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• pp.805-815
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• 2008

Transfer path analysis(TPA) and panel contribution analysis(PCA) have been used widely to reduce interior noise of mechanical systems. TPA enables us to decompose interior noise into air-borne and structure-borne noises and estimate the path contribution of noise sources. PCA is also used to identify the noise contribution of each sub-panel in vibro-acoustic systems. In this paper, TPA and PCA are applied to wheel loader, one of the heavy construction equipments. Firstly, TPA for air-borne noise is conducted to estimate the contribution of air-borne sources using pressure transfer function. Thereafter, TPA for structure -borne noise is employed to verify the results of air-borne source quantification through the synthesis of two results. Secondly, PCA is performed by both TPA using pressure transfer function between panels inside the cabin and boundry element method(BEM) for the cabin of wheel loader with various boundary conditions. As a results, it was found that TPA conducted by experiments and PCA accomplished by both experiments and BEM are very effective methods in analyzing the path and contribution of the noises for reducing an interior noise level in the wheel loader system.

• Proceedings of the Safety Management and Science Conference
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• 2006.11a
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• pp.9-14
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• 2006

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.4
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• pp.315-323
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• 2013

Tire noise is divided into a road noise(structure-borne noise) and a pattern noise(air-borne noise). Whilst the road noise is caused by the structural vibration of the components on the transfer path from tire to car body, the pattern noise is generated by the air-pumping between tire and road. In this paper, a practical method to estimate the pattern noise inside a passenger car is proposed. The method is developed based on the sound intensity and airborne source quantification. Sound intensity is used for identifying the noise sources of tire. Airborne source quantification is used for estimating the sound pressure level generated by each noise source of a tire. In order to apply the airborne source quantification to the estimation of the sound pressure, the volume velocity of each source should be obtained. It is obtained by using metrics inverse method. The proposed method is successfully applied to the evaluation of the interior noises generated by four types of tires with different pattern each other.

• Journal of the KSME
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• v.35 no.10
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• pp.886-895
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• 1995

근래들어 도시의 집중화와 고밀도화, 교통량의 증대 등 사회구조의 급격한 변화로 각종 소음원 들이 증가하고 있으며 소음에 대한 일반인의 관심도 점차 높아지고 있다. 건물의 경우 한정된 공간에서 거주자의 생활을 보다 쾌적하고 편리하게 하기 위해서 각종 설비들이 증가되고, 이들 설비들은 대용량화하는 추세에 있다. 건물내 공간의 기능을 능률적으로 유지하기 위해 설치된 각종 장비(공기조화기, 펌프, cooling tower, 보일러, 냉동기 \ulcorner 발전기 등)에서 발생하는 소음이 직접 실내로 투과되거나 이들이 발생하는 진동이 건물 구조체로 전달되어 실내소음을 야기시키는 경우가 많다. 따라서, 건물을 설계할 때는 실별 용도에 따라 허용소음도를 결정한후 이러한 실내 소음환경을 달성하기 위해 각종 조처를 강구하게 되는데, 이 글에서는 이러한 건물의 실내 소 음도 영향 평가의 하나로 특정 건물의 예를 들어 소음도 계산과 소음의 원인 및 대책에 관해 기술하고자 한다.

• 열병합발전
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• s.71
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• pp.10-14
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• 2009