http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
홍남호(Nam-Ho Hong),김민찬(Min-Chan Kim),현명택(Myung-Taek Hyun) 한국해양공학회 1999 韓國海洋工學會誌 Vol.13 No.2
The time of the onset of double-diffusive convection in time-dependent, nonlinear concentration fields is investigated theoretically. The initially quiescent horizontal fluid layer with a uniform temperature gradient experiences a sudden concentration change from below, but its stable thermal stratification affects concentration effects in such way to invoke convective motion. The related stability analysis, including Soret effect, is conducted on the basis of the propagation theory. Under the linear stability theory the concentration penetration depth is used as a length scaling factor, and the similarity transform for the linearized perturbation equations. The newly obtained stability equations are solved numerically. The resulting critical time to mark the onset of regular cells are obtained as a function of the thermal Rayleigh number, the solute Rayleigh number, and the Soret effect coefficient. For a certain value of the Soret effect coefficient, the stable thermal gradient promote double-diffusive convective motion.
사각형 용기내의 비정상 이중확산유동에 관한 실험적 연구
홍남호(Nam-Ho Hong),김창수(Chang-Su Kim),현명택(Myung-Taek Hyun) 한국해양공학회 1994 韓國海洋工學會誌 Vol.8 No.1
Double-diffusive convection induced by simultaneously-imposed lateral temperature and concentration gradients in a rectangular enclosure with aspect ratio, 2.0, has been studied experimentally for adiabatic and isothermal horizontal boundary conditions. Visual observations show two distinct flow structures depending on the buoyancy ratio. The unicell flow structure is observed for a lower buoyancy ratio while the layered flow structure appears for a higher buoyancy ratio. There exists an unstable flow regime between two buoyancy ratios.
낮은 Pr수를 갖는 순수 물질에서의 진동대류에 관한 수치 해석
현명택,홍남호,이동원 濟州大學校工科大學産業技術硏究所 1997 尖端技術硏究所論文集 Vol.8 No.1
Numerical study was investigated to the transient natural convection in a square cavity. The cavity is filled with the pure substance of a low Prandtl number and the vertical walls are constantly maintained different temperature, while the horizontal boundaries are adiabatic. A control volume approach with a central difference scheme is used to formulate the finite difference equations. The results were presented transient Nusselt number, stream function and temperature distribution. It was found that the flow pattern and heat transfer exhibit time-periodic oscillation at various conditions. The average Nusselt number, the amplitude and the frequency of oscillation increases as the Rayleigh number is increased. The increment of Prandtl number makes that the amplitude and the frequency of oscillation reduced, and average Nusselt number increased.
이동원,홍남호,이종문,현명택 濟州大學校工科大學産業技術硏究所 1995 尖端技術硏究所論文集 Vol.6 No.-
A two-layer, solutally-stratified system with a single interface in a square rectangle is simulated. As noted in previous studies, a unicell flow pattern appears in case of relatively lower buoyancy ratio, while global fluid motion does as layered flow pattern with two convective layers. The averaged Nusselt number develops as the same tendency with pure natural convection and convective effect retards as buoyancy ratio increases. There is no effect with Lewis number, but for N≥0.7 the convective effect is much more delayed in Le=10 than in Le=100 and 300.
이종문,홍남호,이동원,현명택 濟州大學校 産業技術硏究所 1995 산업기술연구소논문집 Vol.6 No.-
A two-layer, solutally-stratified system with a single interface in a square rectangle is simulated. As noted in previous studies, a unicell flow pattern appears in case of relatively lower buoyancy ratio, while global fluid motion does as layered flow pattern with two convective layers. The averaged Nusselt number develops as the same tendency with pure natural convection and convective effect retards as buoyancy ratio increases. There is no effect with Lewis number, but for the convective effect is much more delayed in Le=lO than in Le=100 and 300.
낮은 Pr수를 갖는 순수 물질에서의 진동대류에 관한 수치 해석
이동원,현명택,홍남호 濟州大學校 産業技術硏究所 1997 산업기술연구소논문집 Vol.8 No.1
Numerical study was investigated to the transient natural convection in a square cavity. The cavity is filled with the pure substance of a low Prandtl number and the vertical walls are constantly maintained different temperature. while the horizontal boundaries are adiabatic. A control volume approach with a central difference scheme is used to formulate the finite difference equations. The results were presented transient Nusselt number, stream function and temperature distribution. It was found that the flow pattern and heat transfer exhibit time-periodic oscillation at various conditions. The average Nusselt number. the amplitude and the frequency of oscillation increases as the Rayleigh number is increased. The increment of Prandtl number makes that the amplitude and the frequency of oscillation reduced, and average Nusselt number increased.
權純錫,金善政,洪南湖 동아대학교 공과대학 부설 한국자원개발연구소 1987 硏究報告 Vol.11 No.1
This study on the natural convection has been studied experimentally for the heat transfer characteristics of the horizontal cylinder with one copper fin in air according to the various lengths of fin and the various Rayleigh numbers. The experimental results are as follows; 1. When Rayleigh number is constant, local Nusselt number from the cylinder surface is decreased by increasing fin length. 2. When Rayleigh number is constant, mean fin Nusselt number has the highest value at ℓ=0.2 and the increasing value at ℓ<0.2 and the decreasing value at ℓ≥ 0.2 as the fin length increases. 3. Local fin Nusselt number is increased apparently near the base and rapidly near the tip, and the value near the tip is decreased as dimensionless fin length increases. 4. When fin length is constant, mean fin, mean cylinder and mean total Nusselt number are increased by increasing Rayleigh number.
A Degree Reduction Method for an Efficient QUBO Formulation for the Graph Coloring Problem
강효상,정현우,설채환,홍남호,임현진,엄석현 한국수학교육학회 2024 純粹 및 應用數學 Vol.31 No.1
We introduce a new degree reduction method for homogeneous symmetric polynomials on binary variables that generalizes the conventional degree reduction methods on monomials introduced by Freedman and Ishikawa. We also design an degree reduction algorithm for general polynomials on binary variables, simulated on the graph coloring problem for random graphs, and compared the results with the conventional methods. The simulated results show that our new method produces reduced quadratic polynomials that contains less variables than the reduced quadratic polynomials produced by the conventional methods.