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충격파 경계층 상호작용에서 난류모델 및 난류점성의 효과
전상언(Sang Eon Jeon),박수형(Soo Hyung Park),변영환(Yung Hwan Byun) 한국전산유체공학회 2013 한국전산유체공학회지 Vol.18 No.2
Two compression ramp problems and an impinging shock problem are computed to investigate influence of turbulence models and eddy viscosity on the shock-wave / boundary layer interaction. A Navier-Stokes boundary layer generation code was applied to the generation of inflow boundary conditions. Computational results are validated well with the experimental data and effects of turbulence models are investigated. It is shown that the behavior of turbulence (eddy) viscosity directly affects both the extent of the separation and shock-wave positions over the separation.
전상언(Sang Eon Jeon),박수형(Soo Hyung Park),변영환(Yung Hwan Byun) 한국전산유체공학회 2014 한국전산유체공학회 학술대회논문집 Vol.2014 No.5
A compressible LES code has been developed to simulate turbulent channel flows. A skew-symmetric 4th-order central scheme and the diagonalized ADI scheme with the dual-time stepping were applied to obtain stable and accurate solutions. M=0.5 compressible channel problem was used to verify the developed code and to validate the solution. Effects of time step size and grid resolution were investigated. The present parametric study show that the present LES code can provide accurate and stable solutions for compressible channel flows.
전상언(Sang Eon Jeon),박수형(Soo Hyung Park),김창주(Chang Joo Kim),정기훈(Ki Hoon Chung),정경진(Kyung Jin Jung) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.5
A Reynolds-Averaged Navier-Stokes (RANS) code with transition prediction model is developed and the computational results on an oscillating airfoil are compared with the experimental data for OA209 airfoil. An approximated eN method that can predict transition onset points and the length of transition region is directly applied to the RANS code. The hysteresis loop in dynamic stall is compared for the computational results using transition prediction and fully turbulent models with the experimental data. Results with transition prediction show more correlation with the experimental data than the fully turbulent computation.
전상언(Sang Eon Jeon),박수형(Soo Hyung Park),김상호(Sangho Kim),변영환(Yung Hwan Byun),정경진(Kyung Jin Jung),강인모(Inmo Kang) 한국전산유체공학회 2010 한국전산유체공학회지 Vol.15 No.3
Laminar separation bubble and transitional flow over the NACA0012 are investigated at a moderate range of Reynolds numbers. A Reynolds-Averaged Navier-Stokes code is coupled with an empirical transition model that can predict transition onset points and the length of transition region. Without solving the boundary layer equations, approximated e-N method is directly applied to the RANS code and iteratively solved together. The computational results are compared with the experimental data for the NACA0012 airfoil. Results of transition onset point and the length are compared well with experimental data and Xfoil prediction. The present RANS results show at high angles of attack better agreement with experimental data than Xfoil results using the boundary layer equations.
전상언(Sang Eon Jeon),박수형(Soo Hyung Park),변영환(Yung Hwan Byun),정영석(Youngsuk Jung),오승협(Seung Hyub Oh) 한국추진공학회 2012 한국추진공학회 학술대회논문집 Vol.2012 No.5
액체추진제 공급시스템의 액체포집장치는 추진기관으로 기포가 유입되는 것을 방지하는데 사용한다. 액체포집장치는 차단막의 미세 구멍의 모세관 효과를 이용하여 추진기관에 순수 액체만을 공급한다. 기포점은 액체포집장치의 설계에서 가장 중요한 설계변수이다. 본 논문에서는 문헌조사를 통해 액체포집장치의 성능에 영향을 미치는 변수들을 식별하고 기포점 측정 시험 장치를 구성하였다. Liquid acquisition device in the liquid propellant supply system is required to protect entrance of gas bubble into the propulsion system. The device exploits the capillary effect of micro-sized poles in a screen and supplies pure liquid-phase propellant to the propulsion system. The bubble point is the most important performance parameter in the design of a liquid acquisition device. In this paper, performance parameters affecting the bubble point are identified through literature survey, in order to develop the experimental setup for the bubble point measurement.
전상언(Sang Eon Jeon),박수형(Soo Hyung Park),변영환(Yung Hwan Byun),정영석(Youngsuk Jung),오승협(Seung Hyub Oh) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.12
액체추진제 공급시스템의 액체포집장치는 추진기관으로 기포가 유입되는 것을 방지하는데 사용한다. 액체포집장치는 차단막의 미세 구멍의 모세관 효과를 이용하여 추진기관에 순수 액체만을 공급한다. 기포점은 액체포집장치의 설계에서 가장 중요한 설계변수이다. 본 논문에서는 기포점 측정을 위한 비행시험을 통해 기포점 측정에 미치는 미소중력의 영향을 측정하였다. 실험결과는 이론적 예측치와 잘 일치함을 보여준다. Liquid acquisition device in the liquid propellant supply system is required to protect entrance of gas bubble into the propulsion system. The device exploits the capillary effect of micro-sized poles in a screen and supplies pure liquid-phase propellant to the propulsion system. The bubble point is the most important performance parameter in the design of a liquid acquisition device. The effect of microgravity on the bubble point is investigated by a flight experiment for the bubble point measurement in microgravity. The present experimental results are well correlated with the prediction data.
전상언(Sang Eon Jeon),박수형(Soo Hyung Park),변영환(Yung Hwan Byun),정영석(Youngsuk Jung),오승협(Seung Hyub Oh) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.5
액체추진제 공급시스템의 액체포집장치는 추진기관으로 기포가 유입되는 것을 방지하는데 사용한다. 액체포집장치는 차단막의 미세 구멍의 모세관 효과를 이용하여 추진기관에 순수 액체만을 공급한다. 기포점은 액체포집장치의 설계에서 가장 중요한 설계변수이다. 본 논문에서는 기포점 측정을 위한 실험 장치를 구성하고 기포점을 측정하였다. Liquid acquisition device in the liquid propellant supply system is required to protect entrance of gas bubble into the propulsion system. The device exploits the capillary effect of micro-sized poles in a screen and supplies pure liquid-phase propellant to the propulsion system. The bubble point is the most important performance parameter in the design of a liquid acquisition device. In this paper, measure the bubble point to configure the experiment for the bubble point measurement.
3차원 압축성 모서리에서 충격파와 난류 경계층의 상호작용
전상언(Sang Eon Jeon),박수형(Soo Hyung Park),변영환(Yung Hwan Byun) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.11
3D compression ramp flows are computed to investigate side wall effects on the shock wave / boundary layer interaction. A Reynolds-Averaged Navier-Stokes code and a boundary layer generation code are applied for the generation of inflow boundary conditions. The skin friction and the pressure coefficients on the centerline of the 3D ramp are compared with those from 2D computations. The computation results are validated with the experimental data and a three-dimensionality caused from the side-wall effect is investigated.