http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
LARGE EDDY SIMULATION OF THE COMPRESSIBLE FLOW OVER A CAVITY WITH HIGH ASPECT RATIO
오건제 한국전산유체공학회 2004 한국전산유체공학회지 Vol.9 No.1
Large eddy simulation is used to investigate the compressible flow over a cavity with high aspect ratio. The sub-grid scale stresses are modeled using the dynamic model. The compressible Navier-Stokes equations are solved with the sixth order accurate compact finite difference scheme in the space and the 4th order Runge-Kutta scheme in the time. The buffer zone techniques are used for non-reflecting boundary conditions. The results show the shear layer oscillation over the cavity. The votical disturbances, the roll-up of vorticity, and impingement and scattering of vorticity at the downstream cavity edge can be seen in the shear layer. Several peaks for the resonant frequencies are found in the spectra of the vertical velocity at the center-line. The most energetic peak near the downstream edge is different from that at the center part of the cavity. The pressure has its minimum value in the vortex core inside the cavity, and becomes very high at the downstream face of the cavity. The variation of the model coefficient predicted by the dynamic model is quite large between 0 and 0.3. The model coefficient increases in the stream-wise evolution of the shear layer and sharply decreases near the wall due to the wall effect.
전기 변압기 형상 내부의 밀폐공간 내에서 층류 자연대류 열전달 현상의 수치해석
오건제,Oh, Keon Je 대한설비공학회 1992 설비공학 논문집 Vol.4 No.2
Numerical analysis of the laminar natural convection in an enclosure of the 20KVA oil-immeresed transformer is presented. The core in the transformer is modelled as a rectangular cylinder and calculation is carried out for $Ra=10^3-10^6$. The correlating equation between the inner cylinder mean Nusselt numbers and Rayleigh numbers can be obtained. The conduction and convection regimes for the variation of Rayleigh numbers are well represented in the temperature distributions along the side wall of the inner cylinder. For high Rayleigh numbers, it is found that the recirculating flow in the enclosure above the inner cylinder is divided into two recirculation regions.
오건제 慶南大學校 附設 工業技術硏究所 1998 硏究論文集 Vol.15 No.2
본 연구에서는 여러 가지 형태의 날개 형상을 가진 프로펠러 팬에 대한 성능특성을 해석 하고 날개 형상의 변화가 성능에 미치는 영향에 대하여 연구하였다. 성능곡선의 해석은 점성유동 해석방법을 사용하였으며 팬의 성능에 관한 변수들을 예측하여 비교하였다. Performance characteristics of the axial type propeller fan are numerically investigated using the viscous simulation method. Viscous flow calculations are carried out for the flow in the whole domain employing the Navier-Stokes equations. Computation results of the performance parameters are obtained for the various shape of the fan blade. Predictions show that the blade shape makes a significant difference in the performance curve.
오건제 慶南大學校 附設 工業技術硏究所 1997 硏究論文集 Vol.15 No.1
본 연구에서는 디퓨져 입구에서 작동하는 소형 프로펠러 팬에 대한 성능특성을 해석 하였다. 팬 주위의 점성유동을 Navier-Stokes 방정식을 이용하여 해석하고 이로부터 팬의 성능에 관한 변수들을 예측하여 실험결과와 비교하였다. 예측결과는 실험결과와 비교적 잘 일치 하였으며 본 해석방법이 팬의 성능특성을 잘 해석하고 있음을 알 수 있었다. Numerical prediction of performace characteristics of a small axial type fan operating at the inlet of a diffuser are performed using the Navier-Stokes computation. Viscous flow calculations are carried out for the flow in the whole domain employing the Navier-Stokes equations. The Reynolds stresses for turbulent transport are modelled by the k-εturbulence model. Numerical method is Finite Volume Method with the hybrid convection scheme and the SIMPLE algorithme. Computation results of the performance parameters are obtained for the five cases of the flow rate and compared with the measured ones. Predictions are reasonably following the trend of variations of the measurements and it is conformed that performance characteristics are reasonably resolved in the simulation.