5 research outputs found
Aerodynamic characteristics of a transitional insect flight using multigrid
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Όλ¬Έ (λ°μ¬)-- μμΈλνκ΅ λνμ : κΈ°κ³ν곡곡νλΆ, 2014. 8. κΉκ·ν.κ΅λ΄μμ μλ‘μ΄ λμ€ κ΅ν΅μλ¨μ΄ 건μ€λ κ³νμ μλ€. λμ¬λ κΈνμ² λ (Great Train eXpress) λ νμ¬μ μ§νμ² κ³Ό κ°μ΄ μ§νμ 건μ€λ κ²μ΄λ€. κ·Έλ¬λ μ΅λ μ£Όνμλκ° νμ¬μ μ§νμ² λ³΄λ€ μ½ 2 λ°° λΉ λ₯Έ 200 km/h μ΄λ€. μ΄μ°¨μ μλ ₯μ΄ ν°λμμ μ¦κ°ν λ, 곡기μνκ³Ό κ΄λ ¨λ λ¬Έμ λ€μ΄ μ£Όμκ΄μ¬μ¬λ€ μ€μ νλκ° λλ€. 곡λ ₯λ¬Έμ λ€μ μλ‘ λ€λ©΄ 곡λ ₯ μ ν, μ€ν¬λ¦°λμ΄μ μμ©νλ νμκ³Ό μΉκ°μ μν μ΄λͺ
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Όλ¬Έμμλ μ§νμ² ν°λμμμ 곡λ ₯νμ λΆμκ³Ό GTXμ κ°λ
μ€κ³λ₯Ό μννμλ€. μ°μ , νμ¬ μ§νμ² μλ (100 km/h)μμ GTXμ μλ (200 km/h) λ‘ μ΄μ°¨μλμ μ¦κ°μ λ°λ₯Έ 곡λ ₯ν¨κ³Όλ₯Ό νκ°νμλ€. κ·Έλ¦¬κ³ κ³΅λ ₯ λ³μλ€μ (곡λ ₯μ ν, νμκ³Ό μ°¨λ λ΄λΆμλ ₯ λ³ν) κ²½ν₯μ±μ μ€κ³ λ³μλ€μ (μ°¨λ μ λλΆ νμ, ν°λ λ¨λ©΄μ κ³Ό ν기ꡬ) λ³νμμΌ κ°λ©΄ λΆμνμλ€. κ·Έ νμ, κ²½ν₯μ± λΆμμ ν΅ν GTXμ κ°λ
μ€κ³λ₯Ό μννμλ€. GTXμ κ°λ
μ€κ³λ κ³ μμ΄μ°¨μ μ§νμ² μ μ€κ³ κΈ°μ€μ μν΄ νκ°λμλ€.
ν°λμμ μ΄μ°¨μ 곡λ ₯νΉμ±μ λΆμνκΈ° μν΄ μ μ°μ 체μνμ (Computational Fluid Dynamics) μ¬μ©νμμΌλ©° μΆλμΉ λ°©λ²μΌλ‘ ν΄μμ μννμλ€.
ν΄μ κ²°κ³Όμ λΆμμ ν΅ν΄ GTXμ μ€κ³κ° νμ¬ μ§νμ² κ³Όλ λ€λ₯΄κ² μ§νλμ΄μΌ νλ€λ κ²μ μκ² λμλ€. μ λλΆ νμμ 곡λ ₯μ νμ μ€μ΄κΈ° μνμ¬ νμ¬ μ§νμ² μ 무λ νμμ΄ μλ KTX-μ°μ²κ³Ό κ°μ μ μ ν νμμΌλ‘ μ€κ³λμ΄μΌ νλ©°, ν°λ λ¨λ©΄μ μ νμ¬μ μ§νμ² λ³΄λ€ λμ΄μ ΈμΌ νλ€. μ€ν¬λ¦° λμ΄μ κ²½μ° μ€κ³κΈ°μ€μ κ°νκ° νμνλ©°, GTX μ°¨λμ μΉκ°μ νΈμλ₯Ό μν΄ κΈ°λ°μ΄ μ μ§λμ§ μλ νμ¬ μ§νμ² μ°¨λκ³Όλ λ€λ₯΄κ² κΈ°λ°μ΄ μ μ§λλ μ°¨λμΌλ‘ μ€κ³λμ΄μΌ ν κ²μΌλ‘ νλ¨λλ€.South Korea is proposing to construct a new public transportation system. The Great Train eXpress (GTX) will be built underground as the present subway system. However, the cruise speed will be 200 km/h which is about two times faster than the present subway. When the train speed increases in a tunnel, the problems related to the aerodynamics are the important issues: aerodynamic drag, wind load on the platform screen door and aural discomfort for passengers.
Therefore, we performed the analysis of aerodynamic phenomena in a subway tunnel and conceptual design of GTX. First, the effect of the speed increase on the aerodynamic parameters was investigated as the train speed increases by the speed of GTX (200 km/h) based on the speed of present subway (100 km/h). And the trend of the aerodynamic parameters (aerodynamic drag, pressure wave and pressure change inside the train) is analyzed by changing the design parameters (nose shape, tunnel cross-sectional area and shaft). After that, GTX is designed conceptually from the tendency analysis. The conceptual design is evaluated by the design criteria of the high-speed train and subway.
An analysis to estimate the aerodynamic characteristics of the train in the tunnel is performed using Computational Fluid Dynamics (CFD). Numerical simulations were also performed by the axisymmetric method.
Through the analysis of the simulation results, it is found that the design of GTX should be carried out carefully. The nose shape of GTX should be a streamlined shape like KTX-Sancheon to reduce the aerodynamic drag. The tunnel cross-sectional area should be larger than the present subway tunnel. Tighter criteria about the design of the platform screen door is needed for the high-speed subway like GTX. a sealed train is needed to prevent the internal pressure change from the rapid external pressure change for passenger safety and comfort.
These results are applicable for the basic design of the proposed GTX and tunnel system.Abstract I
Table of Contents III
List of Tables V
List of Figures VI
1. Introduction 1
2. Research objectives 7
3. Method and Validation 9
3.1. Simulation methods 9
3.1.1 Modeling of the train travelling in tunnels 9
3.1.2 Flow solver and turbulence modeling 11
3.1.3 Modeling of the train running 12
3.1.4 Boundary conditions 16
3.2. Validation cases 19
3.2.1 Compression wave generated by the entry of a high-speed train into a tunnel 19
3.2.2 Pressure wave propagation in tunnels-I: 1/164th scale model 25
3.2.3 Pressure wave propagation in tunnels-II: Emmequerung tunnel 30
4. Simulation results and analysis 35
4.1. Effects of design parameters in regard to aerodynamic parameters 35
4.1.1 Aerodynamic drag 35
4.1.1.1 Effect of speed increase 38
4.1.1.2 Effect of nose shape 45
4.1.1.3 Effect of tunnel cross-sectional area 50
4.1.2 Wind pressure on platform screen door 55
4.1.2.1 Effect of speed increase 59
4.1.2.2 Effect of nose shape 61
4.1.2.3 Effect of tunnel cross-sectional area 64
4.1.2.4 Effect of train interference 68
4.1.2.5 Effect of shaft 71
4.1.3 Pressure change inside train 72
4.1.3.1 Effect of speed increase 74
4.1.3.2 Effect of nose shape 78
4.1.3.3 Effect of tunnel cross-sectional area 81
4.1.3.4 Effect of train interference 84
4.1.3.5 Effect of shaft 88
4.2. Conceptual design of GTX considering aerodynamic drag and evaluation 92
4.2.1 Conceptual design 92
4.2.2 Evaluation of wind pressure on platform screen door 97
4.2.2.1 Single train 97
4.2.2.2 Two trains 98
4.2.3 Evaluation of Pressure change inside train 101
4.2.3.1 Single train 101
4.2.3.2 Two trains 105
5. Conclusions 112
References 115
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