• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.837-842
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• 2009

북한강 수계는 여러 하천을 지류로 갖고 유하하고 있으며 하천의 크기 및 본류의 형상에 따라 다양한 방법으로 지류하천이 합류하고 있으나 기존의 지류하천 홍수위 산정방법은 일률적으로 본류의 계획홍수위를 기점홍수위으로 산정하여 계획하고 있다. 따라서 본 연구에는 다양한 지류하천에 대하여 2차원 수치해석을 이용 합류부 지점의 수면형을 해석함으로써 지류 하천의 기존 기점홍수위 적용방법의 적정성에 대하여 검증하였다. 연구방법은 11개 연구대상 지류 하천에 대하여 유입각, 본류와 지류의 유량비 및 하천폭, 본류의 하천 곡선방법에 대하여 수치해석결과를 비교하였다. 유입각에 따른 수위편차를 검토한 결과, 유입각 $90^{\circ}$이하인 지류하천에서 2차원 수치해석 값이 기존 기점홍수위보다 크게 산정되었다. 본류 하천과 지류 하천과의 유량비를 산정하여 수위편차를 검토한 결과 수치적인 경향은 확인할 수 없었다. 본류 하천과 지류 하천의 하폭비를 산정하여 수위편차를 비교한 결과 하폭비가 7이상인 경우 수위편차가 작고, 기존 기점홍수위보다 2차원 수치해석값이 작게 산정되었으며, 하폭비가 $3^{\sim}6$ 범위에서는 수위편차가 가장 크게 발생하는 것을 확인하였다. 본류 하천의 곡선반경을 수위편차와 비교한 결과 곡선반경이 550m이하인 만곡지점의 경우 수위편차가 크게 발생함을 확인할 수 있었다.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.4
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• pp.75-83
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• 2007

Urbanized area has complex terrain with many flow paths. Almost stormwater is drained through pipe network because most area is impervious. And overland flow from the pipe network reform the surface flow. Therefore, it should be considered the drainage system and surface runoff both in urban inundation analysis. It is analyzed by using MIKE FLOOD integrated 1 dimension - 2 dimension model about Incheon Gyo urbanized watershed and compared with the results of 1 dimension model and 2 dimension model. At the result this approach linking of 2 dimension and 1 dimension pipe hydraulic model in MIKE FLOOD give accuracy that offers substantial improvement over earlier approach and more information about inundation such as water dapth, velocity or risk of flood, because it is possible to present storage of overland flow and topographical characteristic of area.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.55-58
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• 2005

Low resistivity zone is observed at the lower part of a CFRD (Concrete Face Rockfill Dam). Generally, CFRD tends not to have any saturated zone within the body, but the result of resistivity survey shows that it is possible for the dam to be saturated under 20m depth with water. The level of reservoir was under 10m from the crest. We suspect that this result may come from the wrong 2D inversion process ignoring the 3D geometry of dams. For the analysis of possibility of distortion by different geometry, we perform the 3D forward modeling for the dam and apply the 2D inversion process. And then we check the point of traditional interpretation of resistivity data. By the analysis, it is found that the result of 2D inversion process of 3D geometry of dams, seems to have deep relation with the reservoir level, and the complex 3D structure hide some internal electrical anomaly of dams from resistivity information.

• Journal of the Korean Geophysical Society
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• v.8 no.4
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• pp.211-214
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• 2005

Low resistivity zone is observed at the lower part of a CFRD (Concrete Face Rockfill Dam). Generally, CFRD tends not to have any saturated zone within the body, but the result of resistivity survey shows that it is possible for the dam to be saturated under 20m depth with water. The level of reservoir was under 10 m from the crest. We suspect that this result may come from the wrong 2D inversion process ignoring the 3D geometry of dams. For the analysis of possibility of distortion by different geometry, we perform the 3D forward modeling for the dam and apply the 2D inversion process. And then we check the point of traditional interpretation of resistivity data. By the analysis, it is found that the result of 2D inversion process of 3D geometry of dams, seems to have deep relation with the reservoir level, and the complex 3D structure hide some internal electrical anomaly of dams from resistivity information.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1851-1855
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• 2011

The accuracy of wheel-rail contact analysis is mainly determined by the methods to find wheel-rail contact points and to calculate contact forces. The 2-dimensional approach which calculates contact points based on the profile curves of the wheel and rail has advantage of reducing calculation time but shortage of approximating the solutions when comparing with 3-dimensional analysis In this analysis, wheelset dynamic behaviors calculated by the approach based on the 2-dimensional wheel-rail curves are compared with those by the 3-dimensional wheel-rail surfaces. Yaw angle and lateral displacement of wheelset center are compared when negotiating a curve.

• Journal of Korea Water Resources Association
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• v.51 no.11
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• pp.971-976
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• 2018

An accurate analysis of pipeline transient is important for proper management and operation of a water distribution systems. The computational accuracy and its cost are two distinct components for unsteady flow analysis model, which can be strength and weakness of three-dimensional model and one-dimensional model, respectively. In this study, we used two-dimensional unsteady flow model with Five-Region Turbulence model (FRTM) with the implementation of interaction between liquid and air Since FRTM has an empirical component to be determined, we explored the response feature of two-dimensional flow model. The relationship between friction behaviour and the variation of undetermined parameter was configured through the comparison between numerical simulations and experimental results.

• Journal of the Korean GEO-environmental Society
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• v.16 no.8
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• pp.45-49
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• 2015

Using 2D numerical analysis that covers the largest section of the dam body, a process is generally performed when evaluating its stability against seepage. The quantity of seepage is first obtained by assuming that its bottom topography is in the simple form of a rectangle, it is then calculated by reflecting its sectional shape during this process of analyzing the seepage quantity. Considering that various forms of dams are being constructed on various types of ground, thanks to more recent technological advances, it is judged more appropriate to draw a conclusion by means of the results on reflecting the realistic shape and topographical conditions of the dam body through 3D numerical analysis. Therefore, this study intends to present a method designed to carry out safety management by evaluating the correct quantity of water leakage that passes only through the dam body, having excluded other factors that include the amount of rainfall through the 3D FEM analysis.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.10
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• pp.1915-1927
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• 1992

A three-dimensional Navier-Stokes code has been developed for analysis of viscous flows through turbomachinery blade rows or other internal passages. The Navier-Stokes equations are written in a cartesian coordinate system, then mapped to a general body-fitted coordinate system. Streamwise viscous terms are neglected and turbulent effects are modeled using the baldwin-Lomax model. Equations are discretized using finite difference method on the stacked C-type grids and solved using LU-ADI decomposition scheme. calculations are made for a two-dimensional cascade in a transonic wind-tunnel to see the infuence of the endwalls. The flow pattern of the three-dimensional flow near the endwall is found to be different from that of the two-dimensional flow due to the existence of the endwalls.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.570-574
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• 2009

벽 근처에서의 흐름(near wall flow)을 해석하기 위한 낮은 레이놀즈수 수정(low-Reynolds number modification)을 포함하는 통계학적 난류모형을 이용한 3차원 비정상 레이놀즈-평균 나비어-스톡스 (URANS) 계산을 실시하여 사각형 수로에서의 중력류를 모의하였다. 3차원 계산 결과를 2차원 URANS 모의에 의한 계산 결과 그리고 실험결과와 비교하였다. 이 연구 결과는 적정 시 공간적 수치해상도를 가지고 벽 근처에서의 흐름을 주의 깊게 직접 해석하는 3차원 URANS 수치모의는 2차원 계산으로는 해석할 수 없는 대규모 Kelvin-Helmholtz 와구조 (vortical structure)의 붕괴(breakdown) 그리고 중력류 선단부에서 발달하는 Lobe-and-Cleft 흐름 불안정 등을 포함하는 중력류의 동적 특성을 높은 정확도로 재현할 수 있음을 보여준다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.04a
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• pp.11-11
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• 1999

액체 램제트 연소기는 흡입공기와 분무, 혼합 그리고 이에 따른 연소 등 일련의 과정에 따라 다수의 복잡한 현상들이 상호 밀접하게 관련되어 있다. 본 연구에서는 액체 램제트 연소기내의 유동특성을 파악하기 위해서 2차원 및 3차원 연소기 형상에 대해서 수치적 실험을 수행하였으며, 격자구성은 연소기에 공기를 공급하고 연료를 분무하는 공기 유입관 영역과 연소실 영역, 그리고 출구 대기 영역으로 나누어 독자적으로 격자를 생성시켰다. 2차원과 3차원 유동해석을 비교하였고 분무모델의 적용에 따른 연소특성 및 분사위치에 따른 연소특성을 비교하였다. 유동해석 결과 2차원과 3차원의 유동특성은 달랐으며, 분무모델을 적용해야 정확한 연소 유동 현상을 예측할 수 있음을 알 수 있었다. 그리고 유입관의 안쪽에 연료의 분사위치를 준 경우가 연소의 안정화에 필요한 재순환영역으로의 연료의 혼합이 잘 되어 유입관 바깥쪽에 연료를 분사시키는 것보다 좋은 분사위치임을 알 수 있었다.