• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2000년도 춘계 학술대회논문집
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• pp.91-98
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• 2000

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.

• 신재생에너지
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• 제9권1호
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• pp.44-50
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• 2013

In order to analyze the characteristics of tidal current power generation system, we measured the output power according to the stream velocity by a water tunnel system and a simulation in MATLAB/Simulink. The water tunnel system consisted of impeller tidal flow transducer and PMSG with rotor in the water. The simulation consisted of PMSG, the tidal current turbine, and back-to-back converter. Also, we simulated the characteristics of output power according to the change of blade length and angular velocity.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.1059-1064
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• 2002

The behavior of an opening and the performance of support system depend upon the load-deformation characteristics of ground and support as well as of the manner and of timing of support installation. The load-deformation characteristics of ground and support are derived by the interaction between ground and support. The interaction between ground and support is qualitatively illustrated by a ground response curve. The behavior of an opening and the performance of support system depend upon the load-deformation characteristics of ground and support as well as of the manner and of timing of support installation. The interaction between ground and support is qualitatively illustrated by a ground response curve. The convergence-confinement method don't need the basic assumptions for a mathematical model. Also This is applicable to general tunnel. Consequently the stability of tunnel must be qualitatively investigated by a ground response curve and quantitatively adjudged by a numerical analysis for the reasonable design of tunnel.

• Geomechanics and Engineering
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• 제11권1호
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• pp.41-58
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• 2016

This paper focuses on the deformation behavior of tunnels crossing a weak zone in conventional tunneling. A three-dimensional finite element model was adopted that allows realistic modeling of the tunnel excavation and the support installation. Using the 3D FE model, a parametric study was conducted on a number of tunneling cases with emphasis on the spatial characteristics of the weak zone such as the strike and dip angle, and on the initial stress state. The results of the analyses were thoroughly examined so that the three-dimensional tunnel displacements at the tunnel crown and the sidewalls can be related to the spatial characteristic of the weak zone as well as the initial stress state. The results indicate that the effectiveness of the absolute displacement monitoring data as early warning indicators depends strongly on the spatial characteristics of the weak zone. It is also shown that proper interpretation of the absolute monitoring data can provide not only early warning for a weak zone outside the excavation area but also information on the orientation and the extent of the weak zone. Practical implications of the findings are discussed.

• 한국지반환경공학회 논문집
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• 제16권12호
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• pp.37-43
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• 2015

터널구조물은 굴착 주변 지반의 강도를 활용하는 구조물로서 지반특성이 가장 중요하다. 단층파쇄대와 같은 취약한 지반 조건이 터널 굴착 구간에 존재하는 경우, 특히 단층파쇄대와 지하수 용출이 동시에 발생하는 조건에서는 터널 굴착 중 과다변위 또는 붕락 등이 자주 발생한다. 이러한 단층파쇄대는 터널 굴착 중 변위 및 붕락의 방향을 결정해주는 중요한 요인이 된다. 단층파쇄대의 규모 및 지표부와의 방향성에 따라 터널 거동 특성이 결정되고 이와 더불어 지하수 용출이 발생되는 경우에는 터널 굴착 중 발생되는 변위 및 붕락 특성이 시간 의존적인 거동을 하게 되는 결정적인 요인이 된다. 단층파쇄대 구간에서 지하수 용출을 해석적인 방법으로 예측하거나 지하수 용출과 단층파쇄대의 상호거동을 분석하였을 경우에 정확하게 예측을 하기가 어렵다. 따라서 단층파쇄대와 지하수가 동시에 발생하는 구간에서는 해석적인 분석방법으로는 한계가 있으므로 실제 시공사례를 분석하여 거동을 종합적으로 예측하는 것이 필요하다. 본 연구에서는 단층파쇄대의 위치에 따른 실제 터널 거동 특성을 분석하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1924-1929
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• 2010

In long tunnel If we reduce the length of system height on catenary system, tunnel construction cost is cut down. It is because of tunnel section curtailment. So that we have review reduction of system height according to tunnel section. We have designed reduction of system height considered characteristics of overhead contact systems within UIC 799 code.

• International Journal of Aeronautical and Space Sciences
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• 제14권1호
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• pp.99-104
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• 2013

Configuration design, analysis, and wind tunnel test of a vane-type multi-function air data probe (MFP) was described. First, numerical analysis was conducted for the initial configuration of the MFP in order to investigate aerodynamic characteristics. Then, the design was modified to improve static and dynamic stability for better response characteristics. The modified configuration design was verified through wind tunnel tests. The test results are also used to verify the accuracy of the analytical method. The analytically estimated aerodynamic damping provided by the Navier-Stokes equation solver correlated well with the wind tunnel test results. According to the calculation, the damping coefficient estimated from ramp motion analysis yielded a better correlation with the wind tunnel test than pitch oscillation analysis.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1328-1332
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• 2010

The enlargement of existing tunnels is required to cope with problems related to traffic congestion. Sometimes, the tunnel traffic must be maintained through existing tunnels during their reconstruction due to non-availability of detours. And excavation by drill and blasting is desired for widening a hard rock tunnel. In this case, the road must be closed for some period for blasting through analyzing of traffic volume. In this paper, a case study on some traffic countermeasures for tunnel enlargement by blasting was performed. And the traffic flow characteristics of some tunnels in domestic main city were analyzed.

• 한국터널지하공간학회 논문집
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• 제2권2호
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• pp.22-31
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• 2000

철도터널에서 오염물질의 거동은 열차의 운행조건 및 터널의 구조 등과 같은 다양한 인자에 의해 영향을 받아 매우 복잡한 양상을 보이게 된다. 본 연구에서는 SES프로그램을 수정하여 해석한 농도계산을 이용하여 철도터널에서 오염물질의 거동특성을 구명하고, 터널의 단면적, 길이 및 열차의 항력계수, 주행속도가 터널의 최대풍속 및 오염농도에 미치는 영향에 대한 분석결과를 제시하였다.

• 대한기계학회논문집
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• 제14권5호
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• pp.1096-1103
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• 1990

본 연구에서는 Fig.1과 같은 열린 경제(open boundary)를 갖는 일반적인 형태 의 3차원 풍동에 대한 공진 특성을 구하여 이를 실험과 비교한다.이런 풍동에 공진 진동수와 일치하는 규칙적인 가진을 주면, 유동 특성은 현저하게 변하게 된다. 일반 적으로, 이러한 임의의 형태를 갖는 풍동의 공진 진동수와 모드는 이론적인 방법으로 예측하기는 매우 힘들다. 이런 경우에 유한요소법은 매우 유용한 방법이다.