http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : 김회동(Heuy-dong Kim) (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
-
김회동(Kim Heuy-Dong),김동현(Kim Dong-Hyeon) 한국철도학회 1998 한국철도학회 학술발표대회논문집 Vol.- No.-
High-speed railway trains entering and leaving tunnels generate finite amplitude pressure wave which propagate back and forth along the tunnels, reflecting at the open ends of the tunnels and at other discontinuities such as ventilation shafts and the train themselves. In present day railways, the magnitudes of the pressure waves are much too small to cause structual damage, but they are a serious potential source of aural discomport for passengers on unsealed trains. Almost always do the pressure waves propagating along the tunnels lead to a hazardous impulse noise near the exit portal of the tunnel. In order to alleviate such undesirable phenomena, some control strategies have been applied to the compression wave propagating inside the tunnel. The objective of the current work is to investigate the effect of tunnel entrance hoods on the entry compression wave at the vicinity of the tunnel entrance. Three types of entrance hoods were tested by the numerical method using the characteristics of method for a wide range of train speeds. The results show that the maximum pressure gradient of compression wave can be considerably reduced by the tunnel entrance hood. Desirable hood shape for reduction of the pressure transients and impulse noise was found to be of abrupt type hood with its cross-sectional area 2.5 times the tunnel area.
-
-
남종순(Jong Soon Nam),이종성(Jong Sung Lee),김회동(Heuy Dong Kim) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
Hysteresis phenomena in fluid flow system have the attention of many researchers for their industrial and engineering applications. However, the hysteresis phenomena in the supersonic internal flow with shock wave have not been investigated compared to those in the supersonic external flow with shock wave satisfactorily. The present work aims at investigating the unsteady behavior of shock position with a three types of two-dimensional supersonic nozzle using CFD. The present computational results were validated with previous experimental data. Unsteady, compressible, axisymmetric, Navier-Stocks equations with Spalart-Allmaras one-equation turbulence model were solved using a fully implicit finite volume scheme. The result obtained with relationship of between the nozzle area expand ratio and hysteresis phenomenon were discussed.
-
정미선(Mi-Seon Jeong),V. R. Sanal Kumar,김회동(Heuy-Dong Kim) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
In steel-making process of iron and steel industry, the purity and quality of steel can be dependent on the<br/> amount of CO contained in the molten metal. Recently, the supersonic oxygen jet is being applied to the<br/> molten metal in the electric furnace and thus reduces the CO amount through the chemical reactions between<br/> the oxygen jet and molten metal, leading to a better quality of steel. In this application, the supersonic oxygen<br/> jet is limited in the distance over which the supersonic velocity is maintained. In order to get longer<br/> supersonic jet propagation into the molten metal, a supersonic coherent jet is suggested as one of the<br/> alternatives which are applicable to the electric furnace system. It has a flame around the conventional<br/> supersonic jet and thus the entrainment effect of the surrounding gas into the supersonic jet is reduced, leading<br/> to a longer propagation of the supersonic jet. In this regard, gasdynamics mechanism about why the<br/> combustion phenomenon surrounding the supersonic jet causes the jet core length to be longer is not yet<br/> clarified. The present study investigates the major characteristics of the supersonic coherent jet, compared<br/> with the conventional supersonic jet. A computational study is carried out to solve the compressible,<br/> axisymmetric Navier-Stokes equations. The computational results of the supersonic coherent jet are compared<br/> with the conventional supersonic jets.
ScienceON연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
