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터널에 진입하는 고속전철에 의한 3차원 점성유동과 압축파 특성에 관한 수치해석적 연구
신창훈(C. H. Shin),박원규(W. G. Park) 한국전산유체공학회 2000 한국전산유체공학회 학술대회논문집 Vol.2000 No.5
The three-dimensional unsteady compressible Full Navier-Stokes equation solver with sliding multi-block method has been applied to analyze three dimensional characteristics of the flow field and compression wave around the high speed train which is entering into a tunnel. The numerical scheme of AF + ADI was used to efficiently solve Navier-Stokes equations in the curvilinear coordinate system. The vortex formation around the nose region was found and the generation of compression wave due to the blockage effects was observed ahead of the train in the form of plane wave. The three dimensional characteristics of the flow field compared to the analytic results were discussed in detail. The variation of pressure of tunnel wall surface and velocity profile of the train are identified as the train enters into a tunnel. The changes in aerodynamic forces and streamlines of each specific sections are also discussed and presented.
터널에 진입하는 고속전철 주위의 3차원 점성유동과 압축과 특성에 관한 수치해석적 연구
신창훈(C. H. Shin),박원규(W. G. Park) 한국전산유체공학회 2000 한국전산유체공학회지 Vol.5 No.3
The three-dimensional unsteady compressible Full Navier-Stokes equation solver with sliding multi-block method has been applied to analyze three dimensional characteristics of the viscous flow field and compression wave around the high speed train which is entering into a tunnel. The numerical scheme of AF + ADI was used to efficiently solve Navier-Stokes equations in the curvilinear coordinate system. The vortex formation owing to the viscous interaction around the train was found and the generation of compression wave due to the blockage effects was observed ahead of the train in the form of plane wave. The three dimensional characteristics of the flow field compared to the analytic results were discussed in detail. The variation of pressure of tunnel wall surface and velocity profile of the train are identified as the train enters into a tunnel. The changes in aerodynamic forces and streamlines of each specific sections are also discussed.
평판형 수압파쇄 균열을 통과하는 다공질유동 특성에 관한 DNS 해석 연구
신창훈(C.H. Shin),박원규(W.G. Park) 한국전산유체공학회 2016 한국전산유체공학회지 Vol.21 No.4
The flow analyses through a porous hydraulic fractures is among the most important tasks in recently developed shale reservoirs but is rendered difficult by non-Darcy effects and geometric changes in the hydraulic fractures during production. In this study, several Computational Fluid Dynamics(CFD) models of hydraulic fractures, with a simple shape such as that of parallel plates, filled with proppants were built. Direct Numerical Simulation(DNS) analyses were then carried out to examine the flow loss characteristics of the fractures. The hydraulic diameters for the simulation models were calculated using the DNS results, and then they were compared with the results from Kozeny’s definition of hydraulic diameter which is most widely used in the flow analysis field. Also, the characteristic parameters based on both hydraulic diameters were estimated for the investigation of the flow loss variation features. Consequently, it was checked in this study that the hydraulic diameter based on Kozeny’s definition is not accordant to the results from the DNS analyses, and the case using the CFD results exhibits f·Re robustness like general pipe flows, whereas the other case using Kozeny’s definition doesn’t. Ultimately, it is expected that discoveries reported in this study would help further porous flow analyses such as hydraulic fracture flows.
정압기 임계유동특성 및 배관망해석 요소로서의 고려에 관한 수치해석적 연구 (II) : 단면적 및 개도 변화
신창훈(C. H. Shin),하종만(J. M. Ha),이철구(C. G. Lee),허재영(J. Y. Her),임지현(J. H. Im),주원구(W. G. Joo) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.11
The major parameters governing the fluid dynamical and thermo-dynamical behavior in the large pipeline network system are friction loss and the pipeline length. But in local pipeline networks and relatively short distance pipeline system, secondary loss and the considerations of the moving states of the fluid machine are also important. One of the major element in local pressure control system is pressure regulator. It causes the variations of the physical properties in that pipeline system. When it is under working, the accurate analysis of the flow properties is so difficult. In this study, some numerical approaches to investigate the critical-flow-characteristics of the pressure regulator have been done according to the variations of the opening ratio or cross-sectional area and the detail examinations and considerations of the pressure regulator as a pipeline network elements have been carried. Finally the flow-flied distributions and critical-flow-characteristics have been presented in detail and the critical flow phenomena and the relation to the opening ratio or cross-sectional-area ratio have been studied.