• 월간 기계설비
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• s.44
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• pp.86-89
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• 1994

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.9
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• pp.615-622
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• 2017

A normal shock wave is initially formed in the shock tube that migrates towards the closed end of the tube, which, in turn, leads to the reflection of shock. Due to the interaction of the reflected shock with the boundary layer, bifurcation of the shock wave takes place. A shock train will be generated after the bifurcated shock wave approaches the contact surface. Until now, only a few studies have been conducted to investigate this shock train phenomenon inside the shock tube. For the present study, a CFD analysis has been performed on a two dimensional axisymmetric model of a shock tube using unsteady, compressible Navier-Stokes equations. In order to investigate the detailed characteristics of the shock train phenomenon, quantitative studies have been performed by varying shock tube length, diameter under fixed diaphragm, and pressure ratio inside a shock tube.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.5
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• pp.618-626
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• 1998

This paper describes a series of fundamental studies on reflection and emission of weak pressure waves from an open end of a pipe. Acoustical theories which have been employed in the plane pressure waves inside a pipe are applied to the present study. The objective of the present study is to investigate the reflection or emission coefficient of pressure wave at an open end of a pipe, the length of open end correction, and the directivity characteristics of the pressure waves emitted from the pipe. The results show that the reflection coefficient of pressure wave at an open end and the length of open end correction decrease for the wave length of pressure wave to increase. It is also found that the reflection coefficient for a baffle plate at the exit of pipe is larger than that for no baffle plate.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.3
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• pp.71-78
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• 2010

The end shape of tube for automobile power steering system has influence on the ability of performance. In this case study, we attempted to optimize the forming process of a small tube using Taguchi experimental design methodology. A preliminary experiment was conducted and four main control factors were selected. The experiment was set up as an $L_9(3^4)$ orthogonal array, and determined the optimal levels of the four factors through the analysis of the experimental results. As a result, the performance characteristic(close adhesion power) of the product was improved about 36%. In addition, the process capability index $C_{pk}$ is enhanced from 0.94 to 6.85.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.544-549
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• 2003

When a shock wave arrives at an open end of tube, an impulse wave is discharged from the tube exit and causes serious noise and vibration problems. In the current study, the effect of the cross-sectional area of tube on the impulse wave is numerically investigated using a CFD method. The Harten-Yee's total variation diminishing(TVD) scheme is used to solve the axisymmetric, two-dimensional, unsteady, compressible Euler equations. With three different cross-sectional areas of tube, the Mach number of the incident shock wave $M_{s}$ is varied between 1.01 and 1.5. The results obtained show that the directivity and magnitude of impulse wave strongly depend upon the Mach number of incident shock wave and are influenced by the tube area. It is also known that the tube cross-sectional area significantly affects the magnitude of impulse wave at or near the tube axis.

• Water for future
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• v.22 no.4
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• pp.435-440
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• 1989

An analytical equation was formulated using the continuity, momentum, and energy equations for the trensients generated in an initially empty piping with a sudden contraction subject to rapid filling with liquid. Also, two mathematical models, MOC and RCT were applied to this particular piping to reveal that the rigid column method is less applicable than the method of characteristics to the piping.

• Journal of architectural history
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• v.16 no.2
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• pp.99-118
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• 2007

Kyedan(戒壇) is an altar to perform a rite of Buddhist Initiation which gives Precept to a Buddhist monk. Sometimes it is called the Place of Precept and Mandala by Sanskrit. In this study, the Sutra of the Tang(唐) Dosun(道宣) regarding First Kyedan of Jetavana-anathapindasyarama(祇園精舍), which was the first temple such as, Kyedandokyung(戒壇圖經), Kiwonsadokyung(祇洹寺圖經), Sabunyul(四分律) were analyzed to find out original form and layout. Ultimately, the study was intended to examine the spatial formation-principle by comparing with Kyedan Temple. The results of this study could be summarized as below. First. Except for Kyedan in Bakryensa, the height of lower stone plate of Buddhist Bell-Shaped Stupa of Korean Kyedan is higher than three storied Kyedan that described in Kyedandokyung. Second. Buddhist Bell-Shaped Stupa above Kyedan was presumed that embodied image of Bell Pedestal and symbolism of overturned-bowl were combined together, when Kyedandokyung and Kiwonsadokyung were referred. It could be examined by the existence of stone lantern. Third. In Korea, the rite of Buddhist initiation that gives Precept in Kyedan has been considered impossible. However, when the rite was conducted, there was a possibility to establish wood stair. It is because that the Buddhist Stupa of Silleuuksa(神勒寺) and Woljeongsa(月精寺), which reflected the image of Kyedan had stone stair. Fourth, The method to build Kyedan of Dosun divided into Large Region and Small Region was applied to the method to construct Stone terrace behind Jeongmyeolbogung(寂滅寶宮) like Tongdosa(通度寺) and complete Kyedan on the stone terrace. In other words, Jeongmyeolbogung became Kyedanwon(戒壇院) and Kyedan, itself became Small Region. The area of Stone terrace became Large Region and naturally, they constituted an Institution. Fifth, Korean Kyedan which is consist of Jeongmyeonlbogung and Kyedan is a Korean original composition principles of Kyedangaram(戒壇伽藍) that can satiate all the functions of Kyedan as a religious subject and the place of the rite of Buddhist initiation, as it had complex of Outdoor Kyedan, which was suggested by the sutra of Dosun and Institution of Kyedan.