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Kweon, Y.H.;Kim, H.D.
- Proceedings of the KSME Conference
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- 2001.11b
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- pp.462-467
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- 2001
The present study addresses a computational work of the weak shock wave propagatings inside a silencer system of automobile exhaust pipe. Four different types of the silencer systems and the initial shock wave Mach number $M_s$ of $1.01\sim1.30$ are applied to investigate their effects on the noise reduction and the flow field in a silencer system. The results obtained from the present computational work are compared with the experimental results. The second order total variation diminishing (TVD) scheme is employed to solve the two dimensional, compressible, unsteady, Euler equations. The present computational results predict the experimental results with a quite good accuracy. Of the four silencer systems applied, the most desirable silencer system to reduce the peak pressure at the exit of the exhaust pipe is discussed.
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전진용;류종관
- The Journal of the Acoustical Society of Korea
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- v.22 no.2
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- pp.88-95
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- 2003
The auditory experiments based on subjective responses were undertaken for the standard heavy and light weight impact noise and rubber ball impact noise, jumping noise to investigate relations between floor Impact noise levels and subjective responses and to establish the upper/lower limits of floor impact noises. As a result, it was shown that relations between floor Impact noise levels and subjective responses was linear and the lower limit of heavy-weight impact noise was L/sub i, Fmax, AW/=46㏈ and the lower limit of light-weight impact noise was L'/sub n,AW/=56㏈. Finally the 3 subjective classes of floor impact noises were established.
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Kim, Ki Ro;Park, Min Jun;Park, Soo Hyung;Lee, Duck Joo;Park, Nam Eun;Im, Dong Kyun
- Journal of the Korean Society for Aeronautical & Space Sciences
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- v.46 no.5
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- pp.376-384
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- 2018
The aerodynamic far-field noise was computed by an acoustic analogy code using the permeable surface for the UH-1H rotor blade in hover. The permeable surface surrounding the blade was constructed to include the thickness noise, the loading noise, and the flow noise generated from the shock waves and the tip vortices. The computation was performed with compressible three-dimensional Euler's equations and Navier-Stokes equations. The high speed impulsive noise was predicted and validated according to the permeable surface locations. It is confirmed that the noise source caused by shock waves generated on the blade surface is a dominant factor in the far-field noise prediction.
https://doi.org/10.5139/JKSAS.2018.46.5.376 인용 PDF KSCI

Kim, HyoJun;Ryu, BongJo
- Transactions of the Korean Society for Noise and Vibration Engineering
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- v.15 no.3 s.96
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- pp.272-279
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- 2005
In this study the optimal isolation system for the prototype HIFD(high impulsive force device) is investigated. For this purpose, firstly, the dynamic behavior of a human body and a transmitted force under specific operation conditions are analyzed through a series of experimental works using the devised test setup. In order to design the optimal dynamic absorbing system, the parameter optimization process is performed using the simplified isolation system model based on the experimental results of linear impulse and transmitted force. Finally, under the parameters satisfying the constraints of the buffering displacement and the transmitted force, the performance of the designed isolation system for the prototype HIFD is evaluated by experiment.
https://doi.org/10.5050/KSNVN.2005.15.3.272 인용 PDF KSCI