http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Lattice Boltzmann Method를 이용한 미소채널 유동 시뮬레이션
이현진(H. J. Lee),김성목(S. M. Kim),노승탁(S. T. Ro) 대한기계학회 2001 대한기계학회 춘추학술대회 Vol.2001 No.9
In micro scale flow, the precedent researchers showed experimentally that there were disparities between results from their experiment and predictions from conventional theory. An important factor, which brings forth the differences, is the dominance of surface forces due to the small characteristic length. Since various surface forces are originated from intermolecular force, it should be considered in the microfluidics Molecular approach rather than continuous approach is appropriate to incorporate the intermolecular force. In this paper, the flow in a microchannel was simulated with the consideration of intermolecular force by the Lattice Boltzmann Method that is from Boltzmann equation based on kinetic theory. The results from present study, pressure gradient and friction factor, are compared with the former experimental results.
마이크로 터보제트 엔진 노즐 유동장에 관한 CFD 전산해석 및 스케일링 특성 연구
이현진(H.J. Lee),안창환(C.H. An),명노신(R.S. Myong),최성만(S.M. Choi),김원철(W.C. Kim) 한국전산유체공학회 2017 한국전산유체공학회지 Vol.22 No.1
Thermal flowfield of a micro turbojet engine was computationally investigated for exhaust nozzles with different aspect ratio and curvature. Special attention was paid to maximum and average temperature of the nozzle surface and the exhaust nozzle plume. The IR signatures of the micro turbojet engine nozzle were then calculated through the narrow-band model based on thermal flowfield data obtained through CFD analysis. Finally, in order to check the similarity of thermal flowfields and IR signature of the sub-scale micro turbojet engine model and the full-scale UCAV propulsion system, several non-dimensional parameters associated with temperature and optical property of plume were introduced. It was shown that, in spite of some differences in actual values of non-dimensional parameters, the scaling characteristics on spectral feature of IR signature and effects of aspect ratio and curvature of nozzle configuration remain similar in sub-scale and full-scale cases.
이현진(H. J. Lee),최현수(H. S. Choi),유호식(H. S. Yoo),정구용(K. Y. Chung),고경철(K. C. Koh),최양일(Y. I. Choi) 충북대학교 동물생명과학연구소 2014 동물생명과학연구 Vol.6 No.-
This study was undertaken to evaluate the quality characteristics of 7 emulsion-type sausages(5 domestic and 2 imported) in domestic market. In the chemical composition, there were large variations in moisture and fat contents of sausages. Moisture contents were 52.4 ? 60.7% and fat contents were 13.9 ? 23.2%, respectively. In the quality characteristics of sausages, pH values were 5.82 ? 6.40 and cook test values were 1.33 ? 11.95%, respectively. In the surface color, L values were 52.83 ? 80.40 and a values were 11.36 ? 23.72, respectively. There were large variation in residual nitrite amount of sausages(2.70 ? 35.64ppm). but the level was below 36ppm and seemed to be acceptable. In the texture profile analysis, there were large variations in cohesiveness and chewiness values among sausages. As a result, there were large variations in chemical composition, surface color and texture profile analysis values among emulsion-type sausages in domestic market, and these results were due to the differences in raw meat and additive ratios.
점성 효과를 반영한 압축성 와류 유동의 선형 안정성 해석기법 개발
이현진(H.J. Lee),오세종(S.J. Oh),박동훈(D.H. Park) 한국전산유체공학회 2020 한국전산유체공학회지 Vol.25 No.3
Physical understanding of vortex flow instability is one of the essential prerequisites for proper prediction and analysis of the behavior of vortex flow encountered in many engineering problems. In this study, a stability analysis code for axisymmetric vortex flow is developed based on the linear stability theory. A stability equation is derived from the governing equations for general compressible flows in the cylindrical coordinate system in order to take into account both the effects of compressibility and viscosity on stability results. The code is validated through analyses on widely-known model vortex problems by comparing the results with those from preceding researches. The comparison of the results confirms that variations of unstable eigenvalues with respect to vortex and disturbance parameters as well as the maximum amplification rate can be obtainable very accurately from the developed code. The effect of viscosity on the instability characteristics of supersonic vortex flow was further analyzed by carrying out the additional analysis. The results show that the analysis of the present study provide a more accurate prediction on linear amplification of disturbances compared to the inviscid analyses carried out in former studies. This also indicates that the present code can be considerably useful for parametric studies on the instability of compressible vortex flows with viscous effects.