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커버 형상을 고려한 고속전철 팬터그래프 공력특성의 수치해석적 연구
강형민(H.M. Kang),김철완(C.W. Kim),조태환(T.H. Cho),김동하(D.H. Kim),윤수환(S.H. Yoon),권혁빈(H.B. Kwon) 한국전산유체공학회 2012 한국전산유체공학회지 Vol.17 No.3
The aerodynamic performance of the pantograph on a high speed train was compared for different pantograph covers which are designed to block the aero-acoustic noise from the pantograph. For the study, two types of cover are designed: wedge and cone types. The lift force of pantograph with cover was compared with the force of pantograph only. The comparison clarified that the cone type cover increases the sideslip angle of the flow and decreases the lift force considerably. However, the wedge type cover changes the flow direction upward and increases the lift force of the pan head. This increment of lift force compensates the decrement of lift force caused by the blocking of the flow into the pantograph lower frame due to cover. Therefore, in case of the wedge type cover, the overall lift force changes slightly compared with the cone type cover.
강형민(H.M. Kang),김철완(C.W. Kim),조태환(T.H. Cho),김동하(D.H. Kim),윤수환(S.H. Yoon),권혁빈(H.B. Kwon) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.11
The aero-acoustic analysis around a pantograph of a high speed train is performed. For the grid system, the real shape of the pantograph is utilized and FLUENT is used for the computation of the unsteady flow around the pantograph. Here, large eddy simulation (LES) model is applied for the calculation of the turbulence and aero-acoustic features of the pantograph are estimated by the Ffowcs Williams-Hawkings (FW-H) model. These numerical results are compared with those of experimental results; the aero-acoustic characteristics of the numerical analysis is similar to those of the experimental results and the difference of noise level is about 8dB(A).
강형민(H.M. Kang),조태환(T.H. Cho),김철완(C.W. Kim),윤수환(S.H. Yoon),권혁빈(H.B. Kwon),박춘수(C.S. Park) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.5
The aerodynamic performance of the pantograph of the next generation high speed train is analyzed. The calculation of the flow around pantograph is carried out by FLUENT; by the steady state flow calculation with κ-ω SST turbulence model, the lift force of the pantograph is computed. For the verification of the numerical schemes and grid systems, flow calculations are performed with the pantograph shape which was used at the experiments performed at Railway Technical Research Institute (RTRI) in Japan. Then, the difference of lift force between numerical and experimental results is about 10%. Therefore, selected numerical schemes and the current grid system is adequate for the analysis and prediction of the aerodynamic performance of pantograph system. Based on these numerical schemes and grid systems, the flow around a pantograph of the next generation high speed train is calculated and the lift force of the pantograph is predicted; the lift force of the pantograph is about 146N.
피토튜브 장착위치 선정을 위한 전진 비행하는 헬리콥터 유동장의 CFD 분석
조현구(H.G. Cho),강영진(Y.J. Kang),김성현(S.H. Kim),명노신(R.S. Myong),조태환(T.H. Cho),박영민(Y.M. Park) 한국전산유체공학회 2008 한국전산유체공학회 학술대회논문집 Vol.2008 No.-
A CFD analysis of helicopter flowfield in forward flight is considered as non-trivial issue because of the complexity of vorticity-dominated flowfield. In this work, a study on the selection of the proper location for the installation of the Pitot probe is conducted using a CFD code which can deal with the interaction of rotor blade vortex and body. To describe the flow patterns for rotating rotor blades and body, the sliding mesh scheme is utilized. Pressure distributions and flow patterns are also analyzed to identify regions free from the interaction of body and wake induced from rotor blades.
이창훈(C. H. Lee),정성기(S. K. Jung),노국현(K. H. Rho),양영록(Y. R. Yang),명노신(R. S. Myong),조태환(T. H. Cho) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.11
The concept of truncated airfoil sections has been suggested in order to extend the operational range of icing tunnels. With proper deflection of the small trailing-edge flap on the truncated airfoil the local pressure distribution may remain very close to that of the full-chord airfoil. The truncated flapped airfoil shape is studied by applying optimization methods. To verify the optimized truncated flapped airfoils, air flow and collection efficiency over the truncated airfoil are compared with the results of the full-scale airfoil by a computational method.
IR 신호 분석을 위한 비행 조건에 따른 노즐 열유동장 해석
전수환(S.H. Chun),양영록(Y.R. Yang),문혁(H. Moon),김준영(J.Y. Kim),명노신(R.S. Myong),조태환(T.H. Cho) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.5
Plume flow-fields of aircraft nozzles are numerically investigated at various flight conditions for infrared signature analysis. A mission profile of subsonic unmanned combat aerial vehicle is considered for the requirement of each mission, associated engine and nozzles are selected through a performance analysis. Numerical results of nozzle plume flow-fields using a CFD code are analyzed in terms of thrust, maximum temperature. It is shown that maximum temperature increase for lower altitude and higher Mach number.