• Structural Engineering and Mechanics
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• 제80권5호
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• pp.553-562
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• 2021

In this paper, a hybrid scaled boundary finite element and finite volume method (SBFEM-FVM) is proposed for simulating hydraulic-fracture propagation in brittle concrete materials. As a semi-analytical method, the scaled boundary finite element method is introduced for modelling concrete crack propagation under both an external force and water pressure. The finite volume method is employed to model the water within the crack and consider the relationship between the water pressure and the crack opening distance. The cohesive crack model is used to analyse the non-linear fracture process zone. The numerical results are compared with experimental data, indicating that the F-CMOD curves and water pressure changes under different loading conditions are approximately the same. Different types of water pressure distributions are also studied with the proposed coupled model, and the results show that the internal water pressure distribution has an important influence on crack propagation.

• Water Engineering Research
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• 제2권3호
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• pp.151-160
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• 2001

A two-dimensional flow model is newly developed. Two-dimensional shallow-water equations are discretized by the finite volume method. A nonorthogonal coordinate system is then employed. The developed model is applied to simulations of flows in a 180 degree curved bend flow. Numerical prediction are compared to available laboratory measurement. A good agreement is observed.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2003년도 추계학술발표대회 개요집
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• pp.36-38
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• 2003

In order to understand the basic knowledge on the model of heat source in hybrid welding, authors have conducted finite element analysis to calculate heat distribution using three heat source models of non-split type and split type(Volume, Volume-Volume, Volume-Surface). From the research result, we can confirm that Volume-Volume heat source of split type is suitable for the analysis of heat distribution.

• 한국수자원학회논문집
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• 제31권3호
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• pp.279-290
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• 1998

충격파의 높이나 속도는 홍수제어조작이나 수로벽과 빠른 유속을 가지는 하천에서 교량의 설계에 중요한 자료가 된다. 따라서 광범위한 조건에서 흐름의 불연속면을 모의할 수 있는 수치모형이 요구된다. 본 연구에서는 천수방정식을 지배방정식으로 한 Godunov 형 유한체적법 모형을 개발하였다. Riemann 해법으로 Roe(1981)의 해법이 사용된다. 이 모형은 본 연구에서 비구조적격자(unstructured grids)를 사용하기 위해 개발된 수정 MUSCL을 도입하였다. 양해법을 쓰는 본 모형은 시간간격을 자동 계산한다. 개발된 모형을 전형적인 이차원 댐 붕괴파 모의, 수리모형 실험에서 행해진 붕괴파 모의, 그리고 수리모형 실험에서 행해진 만곡수로에서의 정상상태 모의 등에 적용하였다. 그 적용결과에 의해 다음과 같이 결론을 내었다. 1)유한체적법은, 충격파 모의를 위한 수치해석 기법인 Godunov 형 방법과 잘 결합될 수 있기 때문에 충격파를 모의하기에 적당한 방법이다. 2)수정 MUSCL과 결합된 유한체적법 모형이 충격파를 잘 포착함으로써 수정 MUSCL의 적용성이 입증되었다.

• 한국수자원학회논문집
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• 제45권5호
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• pp.473-480
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• 2012

고정확도를 보장할 수 있는 Compact Finite Volume Method를 이용하여 수심적분형 흐름 모형과 수심평균된 이송확산 방정식을 해석하는 수치모형 개발과정을 기술하였다. 이차원의 흐름과 파랑의 상호작용에 대한 실험결과와 제시된 수치모형을 이용한 계산결과는 양호하게 일치하였다. 일차원과 이차원공간에서의 흐름에 의한 스칼라의 이송에 관한 수치모의에서도 수차확산이 거의 발견되지 않았고, 매우 정확히 일치하였다. 개수로에서의 난류혼합에 관한 수치모의 결과에서도 합리적인 스칼라의 혼합양상이 관찰되었다.

• Composites Research
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• 제36권6호
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• pp.395-401
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• 2023

본 연구에서는 지도학습 기반 분할기법을 이용하여 단층 촬영된 단방향 복합재료의 유한요소모델링을 실시하였다. 우선, 단방향 복합재료의 형상 정보를 얻기 위해 Micro-CT 스캔을 수행하여 단방향 복합재료의 순수 체적(raw volume)을 획득하였고 여기에 몇 개의 단면을 선택하여 재료의 마이크로 구조인 섬유의 형상을 라벨링하였다. 이후 재료의 단면 이미지와 라벨링한 이미지를 각각 입출력으로 U-net 모델을 훈련시켰다. 이를 사용하여 선택되지 않은 단층촬영 이미지를 섬유형상을 구분하는 분할을 수행하였고 이렇게 생성된 3차원 정보를 이용해서 유한요소모델을 생성하였다. 최종적으로 단방향 복합재료 시편과 유한요소모델의 섬유체적비를 비교하여 제안된 방법의 적절성을 확인하였다.

• 한국전산유체공학회지
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• 제16권4호
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• pp.39-46
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• 2011

A numerical study of a turbulent natural convection in an enclosure with the lattice Boltzmann method (LBM) is presented. The primary emphasis of the present study is placed on investigation of accuracy and numerical stability of the LBM for the turbulent natural convection flow. A HYBRID method in which the thermal equation is solved by the conventional Reynolds averaged Navier-Stokes equation method while the conservation of mass and momentum equations are resolved by the LBM is employed in the present study. The elliptic-relaxation model is employed for the turbulence model and the turbulent heat fluxes are treated by the algebraic flux model. All the governing equations are discretized on a cell-centered, non-uniform grid using the finite-volume method. The convection terms are treated by a second-order central-difference scheme with the deferred correction way to ensure accuracy and stability of solutions. The present LBM is applied to the prediction of a turbulent natural convection in a rectangular cavity and the computed results are compared with the experimental data commonly used for the validation of turbulence models and those by the conventional finite-volume method. It is shown that the LBM with the present HYBRID thermal model predicts the mean velocity components and turbulent quantities which are as good as those by the conventional finite-volume method. It is also found that the accuracy and stability of the solution is significantly affected by the treatment of the convection term, especially near the wall.

• 한국유체기계학회 논문집
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• 제8권3호
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• pp.7-15
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• 2005

A Navier-Stokes code has been developed to simulate the flow through a cross flow fan. It is based on an unstructured finite volume method and uses moving grid technique to model the rotation of the fan. A low Reynolds number turbulence model is used to calculate eddy viscosity. The basic algorithm is SIMPLE. Numerical simulations over a wide range of flow rate aye carried out to validate the code. Comparison of all numerical solutions with experimental data confirms the validity of the present code. Present numerical solutions show a noticeable improvement over a previous numerical method which is based on a model of body force to simulate the rotation of the impeller.

• 한국유체기계학회 논문집
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• 제9권4호
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• pp.27-35
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• 2006

A Navier-Stokes code has been developed to simulate the flow through a cross flow fan. It is based on an unstructured finite volume method and uses moving grid technique to model the rotation of the fan. A low Reynolds number turbulence model is used to calculate eddy viscosity. The basic algorithm is SIMPLE. Numerical simulations over a wide range of flow rate are carried out to validate the code. Comparison of all numerical solutions with experimental data confirms the validity of the present code. Present numerical solutions show a noticeable improvement over a previous numerical method which is based on a model of body force to simulate the rotation of the impeller.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.1174-1178
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• 2005

In this study, flood inundations have been simulated by using the numerical model FLUMEN solving the shallow-water equations with a finite volume method. Before applying to a real problem, the numerical model is first applied to simplified problems. Obtained numerical results are verified by comparing to available analytical solutions and laboratory measurements. Reasonable agreements are observed. The model is then applied to a simulation of flood events with real geometries. The results of the present study provide basic informations for a flood inundation map.