• Title/Summary/Keyword: 3-dimensional numerical analysis

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A Comparative Study on Hydraulic Characteristics of Curved Channel by Hydraulic Model Experiments and Numerical Analysis (수리모형과 수치해석을 통한 만곡부 하천의 수리학적 특성 비교 고찰)

  • Seo, Dong-Il;Choi, Han-Kuy
    • Journal of Industrial Technology
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    • v.27 no.A
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    • pp.85-94
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    • 2007
  • This study, regarding curved channel, was performed to compare and analyze hydraulic characteristics and the speed of water and water level for left bank and right bank through hydraulic model experiments and numerical analysis. Real channels that had characteristics of curved channel were selected as objectives. In order to easily operate one and two dimensional numerical analysis and comparison for total 2.4Km model channel, measuring point was set up as 200m. HEC-RAS model was applied as one dimensional numerical analysis program and SMS model was used as two dimensional numerical analysis program. In respect of speed of water, the average speed of water for right bank recorded 8.33m/s in a model experiment and 3.08m/s, 8.57m/s were average speed of water for right bank in one dimensional and two dimensional numerical analysis. The average speed of water of two dimensional numerical analysis was quite similar to that of model experiments. Also, as for water level, maximum observational errors between one and two dimensional numerical analysis for right and left bank of model experiments were 0.66m, 0.84m and 0.28m, 0.48m for each. It was found that two dimensional numerical analysis had a similar result to hydraulic model experiments. Accordingly, from the result of this study, two dimensional numerical analysis should be used rather than one dimensional numerical analysis, when numerical analysis for curved channel is conducted.

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A study on the 3-dimensional behavior of shaft by the RBM reaming (RBM 굴착에 따른 수직구의 3차원적 거동 연구)

  • 조만섭;이석원;마상준
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.717-724
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    • 2002
  • To investigate the behavior of air-shaft and existing tunnel by excavating the small-diameter shaft into the existing tunnel, prototype air-shaft was constructed and analyzed in this study. Geotechnical characterization was conducted by boring and rock cores obtained were tested in the laboratory. Field monitoring including radial and tangential stresses and displacements was conducted with the 3-dimensional numerical analysis of prototype air-shaft. Results of field monitoring were compared with the numerical results. The results showed that maximum displacement of 2.11mm and maximum tangential stress of 54.0 kg/$\textrm{cm}^2$ were obtained during shaft excavation near the right shoulder of the existing tunnel. The comparison of these field measurements with 3-dimensional numerical analysis showed that much more higher stress was measured during excavation compared to the numerical results even though the trends of stress and displacement were similar.

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A Study on the Validity of 2-Dimensional Analysis of Rock Bolt (록볼트의 2차원 수치해석에 대한 타당성 검토)

  • Seok Jeong Hyeon;Kim Bo Byun;Sik Yang Hyung
    • Tunnel and Underground Space
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    • v.14 no.6 s.53
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    • pp.423-428
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    • 2004
  • The stability of tunnels is usually analyzed as plain strain condition and rock bolts are assumed as 2 dimensional equivalent continuum structures. In this study, 2 and 3 dimensional numerical analyses were conducted to verify the validity of 2 dimensional analysis of rock bolts. Since the results of 2 dimensional analysis showed more than $10\%$ differences in poor rocks, it seems that 3 dimensional analysis is required in poor rocks.

A 3-dimensional Wheel-rail Contact Analysis of Railway Vehicle with 2-point Contacts (2점 접촉을 고려한 철도차량의 3차원 휠-레일 접촉해석)

  • Kang, Ju-Seok
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.3
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    • pp.43-52
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    • 2010
  • In this study, the shapes of the wheel and rail are represented by using 3-dimensional surface functions with surface parameters and a 3-dimensional wheel-rail contact analysis is presented. A whole numerical solution of wheel-rail contact at tread and flange including 2-point contacts can be achieved with the proposed numerical algorithm. Kinematic characteristics such as variances of vertical displacement and roll angle, and variance of wheel radius difference for arbitrary yaw and lateral displacement of wheelset, are determined for the KTX wheel-rail pair as an example. The condition of yaw and lateral displacement occurring 2-point contacts to analyze derailment are compared between standard and worn wheels. Differences of contact characteristics between curved and straight rails are also analyzed.

A 3-Dimensional Numerical Simulation of Impulse Turbine for Wave Energy Conversion

  • Lee, Hyeong-Gu;Lee, Yeon-Won
    • Journal of Advanced Marine Engineering and Technology
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    • v.27 no.4
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    • pp.535-541
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    • 2003
  • This paper describes numerical analysis of the impulse turbine with fixed guide vanes, a high performance hi-directional air turbine having simple structure for wane energy conversion. A 3-dimensional incompressible viscous flow numerical analysis based on the full Reynolds-averaged Wavier-Stokes equations was made to investigate the internal flow behavior Numerical results ate compared with experimental data. As a result, a suitable choice for the one of design factors has been clarified.

3-Dimensional Numerical Analysis for Thermal Stratification in Surgeline in Nuclear Power Plant (원전 밀림관 열성층의 3 차원 수치해석)

  • Kim, Young-Jong;Kim, Maan-Won;Ko, Eun-Mi
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.729-734
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    • 2008
  • A thermal stratification may occur in the horizontal parts of the surge line during operating transients of the pressurizer, which produces relatively high fatigue usage factor. Heat-up transient is the most severe case among the transient conditions. In this study, to study the relationship between the magnitude of thermal stratification and the length of vertical part of the surge line, some parametric fluid-structure interaction (FSI) analyses with different length variables of the vertical part of the surge line were performed for plant heat-up transient condition by using 3-dimensional numerical analysis. The conservativeness of the traditional finite element model for thermal stratification analysis based on the conservative assumption in the surge line was also discussed by comparison of the results of 3-dimensional transient FSI analysis of this study. Stresses calculated with 3-dimensional transient model were considerably reduced comparing with the traditional analysis.

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A Study on the Control of Solitary Waves by Resonator (공진장치에 의한 고립파의 제어에 관한 연구)

  • Lee, Kwang-Ho;Beom, Seong-Sim;Kim, Do-Sam;Park, Jong-Bae;An, Seong-Wook
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.24 no.1
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    • pp.48-57
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    • 2012
  • In this study, 3-dimensional hydraulic model experiment and 3-dimensional numerical analysis were carried out to review the control performance on the solitary waves by attaching the resonator suggested in this study to the openings of the existing rectangular harbors and breakwaters placed in a straight line. In the numerical analysis, TWOPM-3D of 3-D one-field Model for immiscible TWO-Phase flows method using 3-dimensional numerical wave tank was applied, and the validity of the numerical analysis method was verified through comparative analysis between hydraulic experimental results and numerical analysis results. In addition, the effectiveness of the resonator was identified as a result of review on the control performance to control solitary waves of the resonance devices through comparison with cases where the resonators are attached or not.

Numerical Analysis of Eddy Currant Testing with Three Dimensional cracked Pipe by using Finte Element Method (유한요소법을 이용한 3차원 관결함의 와전류탐상 수치해석)

  • Won, Sung-Yean;Lee, Hyang-Beom;Shin, Young-Gil
    • Proceedings of the KIEE Conference
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    • 1999.07a
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    • pp.220-222
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    • 1999
  • This paper presents a numerical analysis of the eddy current testing with cracked pipe using finite element method (FEM). ${\vec{A}},\;{\phi}-{\vec{A}}$ method is adopted for the formulation of 3-dimensional(3-D) FEM with the brick element. The cracks investigated here are the inner and outer surface of axial symmetry, 90 degree circular one. The algorithm of 3-D numerical analysis is employed for the axisymmetric pipe with the cracks. In order to verify the validity of 3-D numerical analysis, the results are compared with those of 2-D analysis with the same type of the model. The differential impedance is obtained by using energy method and its locus are various 8-shaped curves for each cracks. The ICCG method is used for the calculation of a matrix.

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Numerical Analysis of Three-Dimensional Flow in a Forward Curved Centrifugal Fan (전향 원심 송풍기의 3차원 유동에 대한 수치해석)

  • Yoon, Joon-Yong;Maeng, Joo-Sung;Byun, Sung-Joon;Lee, Sang-Hwan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.7
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    • pp.916-923
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    • 2000
  • Numerical study of three-dimensional turbulent flow in a forward curved centrifugal fan is presented. Standard $k-{\varepsilon}$ turbulence model and non-orthogonal curvilinear coordinates arc used to consider the turbulent flow field and complex geometry. Finite Volume approach is adopted for discretization scheme and structured grid system is used to help convergence. Multiblock grid system is used for flow field and divided into five domains that are inlet, outlet, impeller, tip clearance and scroll. It is assumed that the flow field is steady and incompressible. These numerical results are compared with the experimental data inside a rotor and at the fan outlet. Most important flow features are captured through this numerical approach. Finally details of flow field inside a fan are described and analyzed.

A Study of Numerical Wave Tank for 3-Dimensional Free Surface Wave Simulation (3차원 자유표면파 모사를 위한 수치 파수조에 관한 연구)

  • Ha, Y.R.;Kim, Y.J.
    • Journal of Power System Engineering
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    • v.15 no.6
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    • pp.27-34
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    • 2011
  • The increasing capabilities of the computers enable us to utilize various numerical schemes for the time-domain simulations concerned with 3-dimensional free-surface wave problems. There are still difficulties to solve such kind of problems, however. That's because long time simulations with large computational domain are needed in time-domain analysis. So, we need faster and more efficient numerical schemes to get the solutions practically for these problems. In this paper, a high-order spectral/boundary-element method is used for the numerical investigation of physics involved in wave-body interaction. This method is one of the most efficient numerical methods by which the nonlinear gravity waves can be simulated and hydrodynamic forces also can be calculated in time-domain. To get the robust study in these topics, various numerical tests are performed and compared with others' works.