• 한국전산유체공학회지
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• 제15권2호
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• pp.71-78
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• 2010

As a step toward accurate prediction of droplet impingement and ice accretion on aircraft, an Eulerian-based droplet impingement and ice accretion code for air flows around an airfoil containing water droplets is developed. A CFD solver based on the finite volume method was also developed to solve the clean airflow. The finite-volume-based approach for simulating droplet impingement on an airfoil was employed owing to its compatibility with the CFD solver and robustness. For ice accretion module, a simple model based on the control volume is combined with the droplet impingement module that provides the collection efficiency. To validate the present code, it is compared with NASA Glenn IRT (Icing Research Tunnel) experimental data and other well-known icing codes such as LEWICE and FENSAP-ICE. It is shown that the collection efficiency and shape of ice accretion are in good agreement with previous experimental and simulation results.

• 한국전산유체공학회지
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• 제6권3호
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• pp.19-26
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• 2001

An Eulerian-Lagrangian method, so called immersed boundary method, is used for analysing viscous flow around arbitrary bodies, where governing equations are discretized on a regular grid by using a finite volume method. To improve the accuracy of flow near body boundaries, a second-order accurate interpolation scheme is used and a level-set based grid deformation method is presented to construct the adaptive grids around body boundaries. The present scheme is used to simulate steady flow around a semicircular cylinder mounted on the bottom of flow domain and calculated results are validated by results of a body fitted grid method. Finally, present method is applied to a complex flow around multi body and the usefulness is checked by investigating calculated results.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 추계 학술대회논문집
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• pp.37-42
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• 2003

A vorticity-velocity integro-differential formulation of incompressible Wavier-Stokes equations is described, focusing on a scheme for calculating pressure fields in application of the Lagrangian vortex method in connection with panel methods. It deals with the dynamic coupling among velocity, vorticity and pressure, and the Helmholtz decomposition of the velocity field, through a comparative study with the Eulerian finite volume method, we provide an extensive understanding of the Lagrangian vortex methods for numerical simulations of viscous flows around arbitrary bodies.

• 한국전산유체공학회지
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• 제4권2호
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• pp.39-46
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• 1999

The FVM(Finite Volume Method) have been used mainly for the flow analyses in the piston-cylinder. The objective of the present study is to analyze numerically the piston-driven intake flows using the FEM(Finite Element Method). The FEM algorithm used in this study is 4-step time-splitting method which requires much less execution time and computer storage than the velocity-pressure integrated method and the penalty method. And the explicit Lax-Wendroff scheme is applied to nonlinear convective term in the momentum equations to prevent checkerboard pressure oscillations. Also, the ALE(arbitrary Lagrangian Eulerian) method is adopted for the moving grids. The calculated results show good agreement in comparison with those by the FVM and the experimental results by the LDA.

• 한국산학기술학회논문지
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• 제9권2호
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• pp.286-290
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• 2008

본 논문은 고체 추진 로켓의 연소 중에 발생하는 고체추진체의 동적 파괴 현상 및 유체-구조 상호작용을 시뮬레이션 하기 위한 프로그램 개발에 대한 것이다. 개발된 프로그램은 구조해석을 위한 CVFE (cohesive Volumetric Finite Element) 방법과 외재적 ALE (Arbitrary Lagrangian Eulerian) 방법을 응용한 유한요소법 코드와 유동해석을 위한 외재적 비정렬 유한 체적 오일러 코드(Explicit Unstructured Finite Volume Euler code)로 구성된다. 개발된 프로그램의 또 다른 중요한 특징은 균열의 전파와 고체추진체의 변형에 따라 생기는 추진제 형상의 대변형이 발생할 때, 새로 생긴 유체 영역에서의 격자의 확장과 복구되는 능력이다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.460-463
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• 2010

Ice accretion on aircraft surface can greatly impair the aerodynamic performance of aircraft. As an alternative to the traditional Lagrangian particle tracking approach, an Eulerian-based droplet impingement and ice accretion code for air flows containing water droplets was developed A CFD solver was also developed to solve the clean airflow. The results of present method were compared with experimental data and previous icing codes such as LEWICE and FENSAP-ICE and were confirmed to show good agreement each other in qualitative and quantitative ways.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2001년도 춘계 학술대회논문집
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• pp.105-110
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• 2001

An Eulerian-Lagrangian method, so called immersed boundary method, is used for analysing viscous flow around arbitrary bodies, where governing equations are discretized on a regular grid by using a finite volume method. To improve the accuracy of flow near body boundaries, a second-order accurate interpolation scheme is used and a level-set based grid deformation method is presented to construct the adaptive grids around body boundaries. The present scheme is used to simulate steady flow around a semicircular cylinder mounted on the bottom of flow domain and calculated results are validated by results of a body fitted grid method. Finally, present method is applied to a complex flow around multi body and the usefulness is checked by investigating calculated results.

• 한국전산구조공학회논문집
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• 제23권6호
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• pp.675-682
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• 2010

The flood impact pressure acting on a vertical wall resulting from a dam-breaking problem is simulated using a navier-Stokes(N-S) solver. The N-S solver uses Eulerian Finite Volume Method(FVM) along with Volume Of Fluid(VOF) method for 2-D incompressible free surface flows. A Split Lagrangian Advection(SLA) scheme for VOF method is implemented in this paper. The SLA scheme is developed based on an algorithm of Piecewise Linear Interface Calculation(PLIC). The coupling between the continuity and momentum equations is affected by using a well-known Semi-Implicit Method for Pressure-Linked Equations (SIMPLE) algorithm. Several two-dimensional numerical simulations of the dam-breaking problem are presented to validate the accuracy and demonstrate the capability of the present algorithm. The significance of the time step and grid resolution are also discussed. The computational results are compared with experimental data and with computations by other numerical methods. The results showed a favorable agreement of water impact pressure as well as the global fluid motion.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.551-556
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• 2001

The filling pattern technique based on the finite element method and Eulerian mesh advancement approach has been developed to analyze incompressible transient viscous flow with free surfaces. The governing equation for flow analysis is Navier-Stokes equation including inertia and gravity effects. The penalty and predictor-corrector methods are used effectively for finite element formulation. The flow front surface and the volume inflow rate are calculated using the filling pattern technique to select an adequate pattern among four filling patterns at each triangular control volume. Using the proposed numerical technique, the collapse of a dam has been analyzed to predict flow phenomenon of fluid and the predicted front positions versus time have been compared with the reported experimental result.

• 한국전산유체공학회지
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• 제18권2호
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• pp.41-48
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• 2013

Ice accretion on the solid surface is an importance factor in assessing the performance of aircraft and wind turbine blade. Changes in the external shape due to ice accretion can greatly deteriorate the aerodynamic performance. In this study, a three-dimensional upwind-type second-order positivity-preserving finite volume CFD scheme based on the unstructured mesh topology is developed to simulate two-phase flow in atmospheric icing condition. The code is then validated by comparing with NASA IRT experimental data on the sphere. The present results of the collection efficiency are found to be in close agreement with experimental data and show improvement near the stagnation region.